sed with delimiter – any other single character in replacing words or characters

It is not so known fact that this powerful unix world command

sed

could be used with other delimiter than “/” (when replacing words or characters), which is used in 100% of the time in the Internet examples.
You probably know the syntax from the manual like:

s/regexp/replacement/
              Attempt to match regexp against the pattern space.  If successful, replace that portion matched with replacement.  The replacement may  con‐
              tain  the special character & to refer to that portion of the pattern space which matched, and the special escapes \1 through \9 to refer to
              the corresponding matching sub-expressions in the regexp.

The Internet examples always use “/” as shown in the man, BUT you CAN use “#” instead of “/” for example:

s#regexp#replacement#g

or

s:regexp:replacement:g

or you can even use letter character (not a special character as “!@#$%#^”):

sRregexpRreplacementRg

and with “r” lower case (you see not so readable, but possible!)

srregexprreplacementrg

Here are the examples:

sed 's@else@elllllse@g' test.php
sed 's#else#elllllse#g' test.php
sed 's:else:elllllse:g' test.php
sed 's~else~elllllse~g' test.php
sed 's!else!elllllse!g' test.php
sed 'spelsepelllllsepg' test.php
sed 'sRelseRelllllseRg' test.php
#could be paired with "-i", too
sed 'spelsepelllllsepg' -i test.php
sed 'sRelseRelllllseRg' -i test.php

What does it mean to you? The simple implication is you are not forced to escape characters in your regexp and replacement part. Consider you want to replace part of a unix/linux path string: /home/myuser/Desktop/mydirectory1/myfile.log if you use the default “/” you MUST escape all the “/” in your string:

sed 's/\/home\/myuser\/Desktop\/mydirectory1\/myfile.log/\/home\/user\/Desktop\/mydirectory2\/myfile.log/g' test.log

versus the simpler and more readable version with “#”

sed 's#/home/myuser/Desktop/mydirectory1/myfile.log#/home/user/Desktop/mydirectory2/myfile.log#g' test.log

And consider you use an variable:

cat file.test | sed "s/\[version\]/${PKGVERSION}/g"

* additional explanations:

  • /g (or what ever character is used for delimiter like “@”, “:”, “~” and so on) is for “Apply the replacement to all matches to the regexp, not just the first.”
  • -i (used in some of the examples above) is for inline replacement – the file you add in the sed command will be modified and the replacement will be saved in the file (the default behavior is to show the modified output in the standard output – console output)

Clear or delete systemd logs

Systemd linux distros use Journald service to collect and store logs in the system. Here are a couple of tips if you have problems with the space they occupy. It is good that all systemd linux distros support it – CentOS 7, Ubuntu 16+, Fedora, OpenSuse and so on.

TIP 1) Remove the old archive logs older than 10 days with

Time based removal of old logs. It will remove the old files. This command won’t change the configuration, so it just has a temporary effect.

journalctl --vacuum-time=10d

TIP 2) Remove the old archive logs greater than 1G

Size based removal of old logs. It will reduce the size of the logs to this specified size. This command won’t change the configuration, so it just has a temporary effect.

journalctl --vacuum-size=1024M

TIP 3) Show disk usage

[root@srv ~]# journalctl --disk-usage
Archived and active journals take up 785.5M on disk.

TIP 4) Show all logs and information for them

Where are the log files, the size they occupy, the time period of the entries in them and more:

[root@srv0 ~]# journalctl --header
File Path: /run/log/journal/bb5aa69bfa2b483386443ede7a92a45a/system.journal
File ID: 7deaff4610a94c82aab85386597e825b
Machine ID: bb5aa69bfa2b483386443ede7a92a45a
Boot ID: e89507fa3f814b8a96f9d70914c120b0
Sequential Number ID: 541a59d9a68342d3980d86e565a48c7d
State: ONLINE
Compatible Flags:
Incompatible Flags: COMPRESSED-XZ
Header size: 240
Arena size: 102956816
Data Hash Table Size: 178744
Field Hash Table Size: 333
Rotate Suggested: no
Head Sequential Number: 1239405
Tail Sequential Number: 1341511
Head Realtime Timestamp: mon 2018-06-25 10:09:09 UTC
Tail Realtime Timestamp: tue 2018-06-28 00:07:10 UTC
Tail Monotonic Timestamp: 1month 2d 21h 6min 47.287s
Objects: 258136
Entry Objects: 102107
Data Objects: 129585
Data Hash Table Fill: 72.5%
Field Objects: 36
Field Hash Table Fill: 10.8%
Tag Objects: 0
Entry Array Objects: 26406
Disk usage: 98.1M

File Path: /run/log/journal/bb5aa69bfa2b483386443ede7a92a45a/system@541a59d9a68342d3980d86e565a48c7d-000000000011512d-00056f3f3ff56172.journal
File ID: a8e1f042bc144df78f37005b0b555a82
Machine ID: bb5aa69bfa2b483386443ede7a92a45a
Boot ID: e89507fa3f814b8a96f9d70914c120b0
Sequential Number ID: 541a59d9a68342d3980d86e565a48c7d
State: ARCHIVED
Compatible Flags:
Incompatible Flags: COMPRESSED-XZ
Header size: 240
Arena size: 102956816
Data Hash Table Size: 178744
Field Hash Table Size: 333
Rotate Suggested: no
Head Sequential Number: 1134893
Tail Sequential Number: 1239404
Head Realtime Timestamp: fri 2018-06-22 18:32:10 UTC
Tail Realtime Timestamp: mon 2018-06-25 10:09:09 UTC
Tail Monotonic Timestamp: 1month 7h 8min 45.991s
Objects: 263445
Entry Objects: 104512
Data Objects: 131953
Data Hash Table Fill: 73.8%
Field Objects: 34
Field Hash Table Fill: 10.2%
Tag Objects: 0
Entry Array Objects: 26944
Disk usage: 98.1M

File Path: /run/log/journal/bb5aa69bfa2b483386443ede7a92a45a/system@541a59d9a68342d3980d86e565a48c7d-00000000000fc083-00056f0d6ef70320.journal
File ID: 007272b1f181487d83116bee96c40c30
Machine ID: bb5aa69bfa2b483386443ede7a92a45a
Boot ID: e89507fa3f814b8a96f9d70914c120b0
Sequential Number ID: 541a59d9a68342d3980d86e565a48c7d
State: ARCHIVED
Compatible Flags:
Incompatible Flags: COMPRESSED-XZ
Header size: 240
Arena size: 102956816
Data Hash Table Size: 178744
Field Hash Table Size: 333
Rotate Suggested: no
Head Sequential Number: 1032323
Tail Sequential Number: 1134892
Head Realtime Timestamp: wed 2018-06-20 07:06:10 UTC
Tail Realtime Timestamp: fri 2018-06-22 18:32:10 UTC
Tail Monotonic Timestamp: 4w 2h 1min 46.980s
Objects: 263998
Entry Objects: 102570
Data Objects: 133456
Data Hash Table Fill: 74.7%
Field Objects: 37
Field Hash Table Fill: 11.1%
Tag Objects: 0
Entry Array Objects: 27933
Disk usage: 98.1M

File Path: /run/log/journal/bb5aa69bfa2b483386443ede7a92a45a/system@541a59d9a68342d3980d86e565a48c7d-00000000000e3f67-00056ee09376d287.journal
File ID: 4c268268a6e34d6297c7ae9ca01fc31b
Machine ID: bb5aa69bfa2b483386443ede7a92a45a
Boot ID: e89507fa3f814b8a96f9d70914c120b0
Sequential Number ID: 541a59d9a68342d3980d86e565a48c7d
State: ARCHIVED
Compatible Flags:
Incompatible Flags: COMPRESSED-XZ
Header size: 240
Arena size: 102956816
Data Hash Table Size: 178744
Field Hash Table Size: 333
Rotate Suggested: yes
Head Sequential Number: 933735
Tail Sequential Number: 1032322
Head Realtime Timestamp: mon 2018-06-18 01:35:09 UTC
Tail Realtime Timestamp: wed 2018-06-20 07:06:10 UTC
Tail Monotonic Timestamp: 3w 4d 14h 35min 47.248s
Objects: 261498
Entry Objects: 98588
Data Objects: 134059
Data Hash Table Fill: 75.0%
Field Objects: 40
Field Hash Table Fill: 12.0%
Tag Objects: 0
Entry Array Objects: 28809
Disk usage: 98.1M

File Path: /run/log/journal/bb5aa69bfa2b483386443ede7a92a45a/system@541a59d9a68342d3980d86e565a48c7d-00000000000cbf3b-00056eb3ea255b2a.journal
File ID: 7019a721bebe4e00b76410a6e7052c6d
Machine ID: bb5aa69bfa2b483386443ede7a92a45a
Boot ID: e89507fa3f814b8a96f9d70914c120b0
Sequential Number ID: 541a59d9a68342d3980d86e565a48c7d
State: ARCHIVED
Compatible Flags:
Incompatible Flags: COMPRESSED-XZ
Header size: 240
Arena size: 102956816
Data Hash Table Size: 178744
Field Hash Table Size: 333
Rotate Suggested: yes
Head Sequential Number: 835387
Tail Sequential Number: 933734
Head Realtime Timestamp: fri 2018-06-15 20:18:10 UTC
Tail Realtime Timestamp: mon 2018-06-18 01:35:09 UTC
Tail Monotonic Timestamp: 3w 2d 9h 4min 45.972s
Objects: 260794
Entry Objects: 98348
Data Objects: 134060
Data Hash Table Fill: 75.0%
Field Objects: 33
Field Hash Table Fill: 9.9%
Tag Objects: 0
Entry Array Objects: 28351
Disk usage: 98.1M

File Path: /run/log/journal/bb5aa69bfa2b483386443ede7a92a45a/system@541a59d9a68342d3980d86e565a48c7d-00000000000b2fac-00056e827d3375dd.journal
File ID: 61c16e8acc364d97b8c0c7cc2afcb6ec
Machine ID: bb5aa69bfa2b483386443ede7a92a45a
Boot ID: e89507fa3f814b8a96f9d70914c120b0
Sequential Number ID: 541a59d9a68342d3980d86e565a48c7d
State: ARCHIVED
Compatible Flags:
Incompatible Flags: COMPRESSED-XZ
Header size: 240
Arena size: 102956816
Data Hash Table Size: 178744
Field Hash Table Size: 333
Rotate Suggested: no
Head Sequential Number: 733100
Tail Sequential Number: 835386
Head Realtime Timestamp: wed 2018-06-13 09:20:08 UTC
Tail Realtime Timestamp: fri 2018-06-15 20:18:10 UTC
Tail Monotonic Timestamp: 3w 3h 47min 46.827s
Objects: 264298
Entry Objects: 102287
Data Objects: 134043
Data Hash Table Fill: 75.0%
Field Objects: 33
Field Hash Table Fill: 9.9%
Tag Objects: 0
Entry Array Objects: 27933
Disk usage: 98.1M

File Path: /run/log/journal/bb5aa69bfa2b483386443ede7a92a45a/system@541a59d9a68342d3980d86e565a48c7d-000000000009966a-00056e4cbbb6ebfc.journal
File ID: c90df7bdc4654ab7a4ac955c74a779a3
Machine ID: bb5aa69bfa2b483386443ede7a92a45a
Boot ID: e89507fa3f814b8a96f9d70914c120b0
Sequential Number ID: 541a59d9a68342d3980d86e565a48c7d
State: ARCHIVED
Compatible Flags:
Incompatible Flags: COMPRESSED-XZ
Header size: 240
Arena size: 102956816
Data Hash Table Size: 178744
Field Hash Table Size: 333
Rotate Suggested: no
Head Sequential Number: 628330
Tail Sequential Number: 733099
Head Realtime Timestamp: sun 2018-06-10 17:12:09 UTC
Tail Realtime Timestamp: wed 2018-06-13 09:19:10 UTC
Tail Monotonic Timestamp: 2w 4d 16h 48min 46.993s
Objects: 263295
Entry Objects: 104770
Data Objects: 131816
Data Hash Table Fill: 73.7%
Field Objects: 37
Field Hash Table Fill: 11.1%
Tag Objects: 0
Entry Array Objects: 26670
Disk usage: 98.1M

File Path: /run/log/journal/bb5aa69bfa2b483386443ede7a92a45a/system@541a59d9a68342d3980d86e565a48c7d-000000000007fd20-00056e16f3135f30.journal
File ID: 32915d651dd84728b9e4a33a97b480cf
Machine ID: bb5aa69bfa2b483386443ede7a92a45a
Boot ID: e89507fa3f814b8a96f9d70914c120b0
Sequential Number ID: 541a59d9a68342d3980d86e565a48c7d
State: ARCHIVED
Compatible Flags:
Incompatible Flags: COMPRESSED-XZ
Header size: 240
Arena size: 102956816
Data Hash Table Size: 178744
Field Hash Table Size: 333
Rotate Suggested: no
Head Sequential Number: 523552
Tail Sequential Number: 628329
Head Realtime Timestamp: fri 2018-06-08 01:02:10 UTC
Tail Realtime Timestamp: sun 2018-06-10 17:12:09 UTC
Tail Monotonic Timestamp: 2w 2d 41min 46.200s
Objects: 263287
Entry Objects: 104778
Data Objects: 131696
Data Hash Table Fill: 73.7%
Field Objects: 36
Field Hash Table Fill: 10.8%
Tag Objects: 0
Entry Array Objects: 26775
Disk usage: 98.1M
[root@srv0 ~]#

* Deleting logs

[root@srv0 ~]# journalctl --vacuum-size=128M
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a33241-000570199db5be3c.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a34463-0005701a0b24d0fc.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a3568c-0005701a79e388c7.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a36899-0005701ae529f439.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a37ac8-0005701b50781f62.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a38cde-0005701bbd3b60c3.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a39ef6-0005701c28dcf40e.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a3b0f1-0005701c9416ee94.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a3c309-0005701cffe19015.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a3d521-0005701d6c79b9cb.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a3e748-0005701dd7c60e79.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a3f92d-0005701e48413eb8.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a40b0a-0005701ec83a0c74.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a41ce2-0005701f3fdcadc6.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a42f04-0005701fabfefbca.journal (8.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a4410e-000570201757a256.journal (120.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a60a8f-0005702ac025bb0c.journal (120.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a7d254-000570359f2bd7eb.journal (120.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000a99a34-000570405b5e812e.journal (120.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000ab639b-0005704b05553c7d.journal (120.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000ad2c3e-00057055cb403fae.journal (120.0M).
Deleted archived journal /var/log/journal/9be717e698354ec481abb641cf4085c3/system@79d0440cc1174c2db132b707a0567bcb-0000000000aef5c8-000570607686fd78.journal (120.0M).
Vacuuming done, freed 960.0M of archived journals from /var/log/journal/9be717e698354ec481abb641cf4085c3.

Replace an old IP with new one in all files of all sub-directories recursively

Here is a quick Linux tip for those who want to replace their old IP with new one for all files in a given directory and all its sub-directories recursively:

find [path-to-directory] -type f -print0 | xargs -0 sed -i 's[old-IP-escape-dot]/[new-IP]/g'

Quick example:

find /etc/nginx/ -type f -print0 | xargs -0 sed -i 's/192\.168\.10\.124/10.10.10.224/g'

As you can see the directory is “/etc/nginx” and replace it with the directory where are your (configuration) files are. We are replacing old IP=192.168.10.124 with the new one 10.10.10.224, so after the execution of the above line you’ll get modified files with IP 10.10.10.224.
You must escape the dot “.” in the IP!

Configure and mount samba share in Supermicro IPMI Virtual media (CD-ROM)

Having many Supermicro servers we used multiple times Virtual Media to install, diagnose and rescue Supermicro server. It is really simple to open the Console Redirection – java web start and just mount the ISO file from Virtual Media -> ISO File, but this way if your server is not local to your network and it is located in a colocation as it should be the connection is slow and in many cases bogus! Because it uses UDP it happened many times to remount or just to lose the connection and the media to disappear in the middle of the booting/loading process from the installation media, for example. And probably you have noticed there is additional option in the web interface of mounting ISO file from a windows share. Of course, in linux world it might be samba share as in our case and the share could be easily configured on a server in your colocation.
And we noticed was several times we have no problems using it, but some time the share could not be even saved and respectively could not be mounted. No error reported, just the edit boxes resets to blank and apparently everything was the same as the previous box, which it worked as a charm!
Here are the steps to enable one of your CentOS 7 servers to share a resource and to use it in your Supermicro IPMI KVM. The server is selinux enabled and the policy is Enforcing.

STEP 1) Install samba server in CentOS 7

[root@srv0 ~]# yum -y install samba samba-client samba-common
Loaded plugins: fastestmirror
Determining fastest mirrors
epel/x86_64/metalink                                                                                                                           |  30 kB  00:00:00     
 * base: mirrors.neterra.net
 * epel: mirrors.neterra.net
 * extras: mirrors.neterra.net
 * updates: mirrors.neterra.net
base                                                                                                                                           | 3.6 kB  00:00:00     
epel                                                                                                                                           | 3.2 kB  00:00:00     
extras                                                                                                                                         | 3.4 kB  00:00:00     
updates                                                                                                                                        | 3.4 kB  00:00:00     
(1/7): base/7/x86_64/group_gz                                                                                                                  | 166 kB  00:00:00     
(2/7): epel/x86_64/group_gz                                                                                                                    |  88 kB  00:00:00     
(3/7): base/7/x86_64/primary_db                                                                                                                | 5.9 MB  00:00:00     
(4/7): extras/7/x86_64/primary_db                                                                                                              | 147 kB  00:00:00     
(5/7): updates/7/x86_64/primary_db                                                                                                             | 2.0 MB  00:00:00     
(6/7): epel/x86_64/updateinfo                                                                                                                  | 932 kB  00:00:00     
(7/7): epel/x86_64/primary                                                                                                                     | 3.5 MB  00:00:00     
epel                                                                                                                                                      12584/12584
Package samba-client-4.7.1-6.el7.x86_64 already installed and latest version
Package samba-common-4.7.1-6.el7.noarch already installed and latest version
Resolving Dependencies
--> Running transaction check
---> Package samba.x86_64 0:4.7.1-6.el7 will be installed
--> Processing Dependency: samba-libs = 4.7.1-6.el7 for package: samba-4.7.1-6.el7.x86_64
--> Processing Dependency: samba-common-tools = 4.7.1-6.el7 for package: samba-4.7.1-6.el7.x86_64
--> Processing Dependency: libxattr-tdb-samba4.so(SAMBA_4.7.1)(64bit) for package: samba-4.7.1-6.el7.x86_64
--> Processing Dependency: libaio.so.1(LIBAIO_0.4)(64bit) for package: samba-4.7.1-6.el7.x86_64
--> Processing Dependency: libaio.so.1(LIBAIO_0.1)(64bit) for package: samba-4.7.1-6.el7.x86_64
--> Processing Dependency: libxattr-tdb-samba4.so()(64bit) for package: samba-4.7.1-6.el7.x86_64
--> Processing Dependency: libaio.so.1()(64bit) for package: samba-4.7.1-6.el7.x86_64
--> Running transaction check
---> Package libaio.x86_64 0:0.3.109-13.el7 will be installed
---> Package samba-common-tools.x86_64 0:4.7.1-6.el7 will be installed
---> Package samba-libs.x86_64 0:4.7.1-6.el7 will be installed
--> Processing Dependency: libpytalloc-util.so.2(PYTALLOC_UTIL_2.1.9)(64bit) for package: samba-libs-4.7.1-6.el7.x86_64
--> Processing Dependency: libpytalloc-util.so.2(PYTALLOC_UTIL_2.1.6)(64bit) for package: samba-libs-4.7.1-6.el7.x86_64
--> Processing Dependency: libpytalloc-util.so.2(PYTALLOC_UTIL_2.0.6)(64bit) for package: samba-libs-4.7.1-6.el7.x86_64
--> Processing Dependency: libpytalloc-util.so.2()(64bit) for package: samba-libs-4.7.1-6.el7.x86_64
--> Running transaction check
---> Package pytalloc.x86_64 0:2.1.10-1.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

======================================================================================================================================================================
 Package                                        Arch                               Version                                     Repository                        Size
======================================================================================================================================================================
Installing:
 samba                                          x86_64                             4.7.1-6.el7                                 base                             661 k
Installing for dependencies:
 libaio                                         x86_64                             0.3.109-13.el7                              base                              24 k
 pytalloc                                       x86_64                             2.1.10-1.el7                                base                              17 k
 samba-common-tools                             x86_64                             4.7.1-6.el7                                 base                             463 k
 samba-libs                                     x86_64                             4.7.1-6.el7                                 base                             275 k

Transaction Summary
======================================================================================================================================================================
Install  1 Package (+4 Dependent packages)

Total download size: 1.4 M
Installed size: 3.8 M
Downloading packages:
(1/5): libaio-0.3.109-13.el7.x86_64.rpm                                                                                                        |  24 kB  00:00:00     
(2/5): pytalloc-2.1.10-1.el7.x86_64.rpm                                                                                                        |  17 kB  00:00:00     
(3/5): samba-4.7.1-6.el7.x86_64.rpm                                                                                                            | 661 kB  00:00:00     
(4/5): samba-common-tools-4.7.1-6.el7.x86_64.rpm                                                                                               | 463 kB  00:00:00     
(5/5): samba-libs-4.7.1-6.el7.x86_64.rpm                                                                                                       | 275 kB  00:00:00     
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                                                 4.5 MB/s | 1.4 MB  00:00:00     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : pytalloc-2.1.10-1.el7.x86_64                                                                                                                       1/5 
  Installing : samba-libs-4.7.1-6.el7.x86_64                                                                                                                      2/5 
  Installing : samba-common-tools-4.7.1-6.el7.x86_64                                                                                                              3/5 
  Installing : libaio-0.3.109-13.el7.x86_64                                                                                                                       4/5 
  Installing : samba-4.7.1-6.el7.x86_64                                                                                                                           5/5 
  Verifying  : libaio-0.3.109-13.el7.x86_64                                                                                                                       1/5 
  Verifying  : samba-libs-4.7.1-6.el7.x86_64                                                                                                                      2/5 
  Verifying  : samba-common-tools-4.7.1-6.el7.x86_64                                                                                                              3/5 
  Verifying  : samba-4.7.1-6.el7.x86_64                                                                                                                           4/5 
  Verifying  : pytalloc-2.1.10-1.el7.x86_64                                                                                                                       5/5 

Installed:
  samba.x86_64 0:4.7.1-6.el7                                                                                                                                          

Dependency Installed:
  libaio.x86_64 0:0.3.109-13.el7        pytalloc.x86_64 0:2.1.10-1.el7        samba-common-tools.x86_64 0:4.7.1-6.el7        samba-libs.x86_64 0:4.7.1-6.el7       

Complete!
[root@srv0 ~]#

STEP 2) Configure samba server CentOS 7 for the purpose of using it in IPMI Virtual share.

We are going to use a share without login credentials, because our KVM IP are always local ones and accessed via a vpn network and in addition only the network of the IPMI IPs could access the share (the samba server has a firewall configured).
Set the configuration file of the samba server – one directory storing the files shared with no login credentials (no username/password means anonymous login).
The configuration file is:

/etc/samba/smb.conf

[global]
workgroup = WINSHARE
server string = Samba Server %v
netbios name = centossrv
security = user
map to guest = bad user
dns proxy = no
#============================ Share Definitions ============================== 
[share]
path = /mnt/storage1/samba
browsable =yes
writable = no
guest ok = yes
read only = yes

As you can see we use “/mnt/storage1/samba” for our directory where the ISO files will be located. Change this path if you want to put your ISO files somewhere else.
Set the right permissions for the directory and selinux (if you server is not selinux enabled, you could skip the selinux part) and run the samba daemon:

[root@srv0 ~]# mkdir /mnt/storage1/samba
[root@srv0 ~]# chown -R nobody:nobody /mnt/storage1/samba/
[root@srv0 ~]# semanage fcontext -a -t samba_share_t '/mnt/storage1/samba(/.*)?'
[root@srv0 ~]# restorecon -Rv /mnt/storage1/samba/
restorecon reset /mnt/storage1/samba context unconfined_u:object_r:unlabeled_t:s0->unconfined_u:object_r:samba_share_t:s0
[root@srv0 ~]# cd /mnt/storage1/samba/
[root@srv0 samba]# wget http://mirror.leaseweb.com/centos/7.5.1804/isos/x86_64/CentOS-7-x86_64-Minimal-1804.iso
--2018-06-01 14:15:42--  http://mirror.leaseweb.com/centos/7.5.1804/isos/x86_64/CentOS-7-x86_64-Minimal-1804.iso
Resolving mirror.leaseweb.com (mirror.leaseweb.com)... 37.58.58.140, 2a00:c98:2030:a034::21
Connecting to mirror.leaseweb.com (mirror.leaseweb.com)|37.58.58.140|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 950009856 (906M) [application/octet-stream]
Saving to: ‘CentOS-7-x86_64-Minimal-1804.iso’

100%[============================================================================================================================>] 950,009,856 40.1MB/s   in 33s    

2018-06-01 14:16:15 (27.3 MB/s) - ‘CentOS-7-x86_64-Minimal-1804.iso’ saved [950009856/950009856]

[root@srv0 samba]# chown nobody:nobody CentOS-7-x86_64-Minimal-1804.iso
[root@srv0 samba]# systemctl start smb
[root@srv0 samba]# systemctl status smb
● smb.service - Samba SMB Daemon
   Loaded: loaded (/usr/lib/systemd/system/smb.service; disabled; vendor preset: disabled)
   Active: active (running) since Fri 2018-06-01 14:17:57 UTC; 20s ago
 Main PID: 31961 (smbd)
   Status: "smbd: ready to serve connections..."
    Tasks: 4
   Memory: 19.0M
   CGroup: /system.slice/smb.service
           ├─31961 /usr/sbin/smbd --foreground --no-process-group
           ├─31964 /usr/sbin/smbd --foreground --no-process-group
           ├─31965 /usr/sbin/smbd --foreground --no-process-group
           └─31966 /usr/sbin/smbd --foreground --no-process-group

Jun 01 14:17:56 srv0@local systemd[1]: Starting Samba SMB Daemon...
Jun 01 14:17:57 srv0@local smbd[31961]: [2018/06/01 14:17:57.761913,  0] ../lib/util/become_daemon.c:124(daemon_ready)
Jun 01 14:17:57 srv0@local smbd[31961]:   STATUS=daemon 'smbd' finished starting up and ready to serve connections
Jun 01 14:17:57 srv0@local systemd[1]: Started Samba SMB Daemon.

Configure the firewall to allow only connections from the IPMI KVM IP networks (or a single IP if you need to expose it in the Internet). You can work with build in zone “trusted”, but here we prefer more generic approach, which could be used not only for local IP networks but for real IPs:

[root@srv0 samba]# firewall-cmd --new-zone=smbshare --permanent
success
[root@srv0 samba]# firewall-cmd --zone=smbshare --add-source=192.168.7.0/24 --permanent
success
[root@srv0 samba]# firewall-cmd --zone=smbshare --add-service=samba --permanent
success
[root@srv0 samba]# firewall-cmd --zone=smbshare --add-service=samba-client --permanent
success
[root@srv00 samba]# firewall-cmd --reload
success
[root@srv00 samba]# firewall-cmd --zone=smbshare --list-all
smbshare (active)
  target: default
  icmp-block-inversion: no
  interfaces: 
  sources: 192.168.7.0/24
  services: samba samba-client
  ports: 
  protocols: 
  masquerade: no
  forward-ports: 
  source-ports: 
  icmp-blocks: 
  rich rules: 

[root@srv00 samba]#

STEP 3) Mount a disk in IPMI Virutal Media and boot from it

You could check our additional tutorial for it here –

STEP 3.1) Fill “Share host” and “Path image” only, because we configured our samba share without a password

main menu
Image on Windows Share

STEP 3.2) Upon a successful configuration saving you’ll get a confirmation dialog.

If no confirmation is shown you would not be able to mount the share, check out our Troubleshooting below!

main menu
Save configuration of Image on Windows Share

STEP 3.3) After saving the configuration click on “Mount” to load your ISO file in the virtual CD-ROM.

main menu
Mount Image on Windows Share

STEP 3.4) This dialog is always shown no matter there is such share or not: “Please check the device status to confirm whether the image is mounted/unmounted.”

main menu
Check device status

STEP 3.5) If the Supermicro IPMI accessed successfully the share resource it would mount it (load the ISO file as s CD in the virtual CD-ROM).

If not the three Device 1,2,3 will show the same: “No disk emulation set.”, which means the samba share is not accessible, check the permissions for the file and the firewall first (and the logs files, too).

main menu
There is an iso file mounted

* Troubleshooting

– if you click on button “Save” and just nothing happen – no dialog for successful saving and no dialog at all, probably there is a Javascript error, try to open the web interface from a different browser with clean history or click ctrl+F5 when loading the Virtual Media page! More in Cannot save and mount a Supermicro IPMI Virtual media mount – javascript error?

Cannot save and mount a Supermicro IPMI Virtual media mount – javascript error?

If you have multiple Supermicro servers with many different versions of IPMI KVM software installed it could happen your browser to cache some of the JavaScript and other static content to reuse them, but it could very unpleasant when you have different version of IPMI software on different servers and you might notice strange behavior of the web interface! Especially if you use ssh tunneling to access your multiple Supermicro IPMI KVMs from local IP on your computerTunneling the IPMI/KVM ports over ssh (supermicro ipmi ports)

One of the big problems we have when we wanted to mount a Virtual Media

from a windows share (samba share in our case) in IPMI KVM web interface -> Virtual Media -> CD-ROM image -> Save and when the Save is clicked just nothing happen (sometimes it triggers a reload of the iframe) – no error nothing and no confirmation for successful save! At first it seems the web interface accepted the “Share Host” and “Path to Image”:

main menu
Fill “Share Host” and “Path to Image”

but when you click “Mount” it does not mount the media:
main menu
no disk emulation set

and when you reload the CD-ROM image page you get again blank edit boxes or (the old values):
main menu
Old values

Probably a refresh will get the values blank:
main menu
Blank edit boxes

And if you check your browser console you’ll see there is a JavaScript error:

Uncaught ReferenceError: FocusOnErrorSpecificCharSet3 is not defined

The error might be different, this was in our case. the problem was

the browser cached “https://192.168.0.170/js/utils.js”

from one of the previous servers and there the version of the IPMI KVM software was different and apparently the

/js/utils.js

was throwing an error and not working (this function did not exist in some older Supermicro IPMI KVM versions, the file is there but it is slightly different). The solution is so simple!

Just refresh the page with CTRL+F5 or delete the history or use another browser.

Such a simple problem, but could lead to big problems if you try to use the mount virtual media. In fact look for problems in the JavaScript if you cannot save the configuration in the “Share Host” and “Path to Image”, because when saving the IPMI do not check if there is a live “Share Host” with a windows/samba share and an image there, the software just check for special in “Shared” characters like:

var SpeficCharFilter = /[,; &'"<>\\=$|^?*~`()\[\]\{\}#%]/;

And for the password:

var SpeficCharFilter = /[,; &'"<>\\=$|^?~`()\[\]\{\}#%]/;

But in both cases you’ll get an alert with an error.

So to summer it up if you put IP and a path to the windows share of Virtual Media and click “Save” and nothing happen – no confirmation for successful saving you got a JavaScript error and probably your browser cached one of the JavaScript files, the solution is simple just refresh with CTRL+F5 or load from different browser!
We often use ssh tunneling for IPMI KVM accessTunneling the IPMI/KVM ports over ssh (supermicro ipmi ports) and different version of the static files of the supermicro IPMI web interface are cached locally, which as you can see could have really bad consequences!

Working Save button

click Save button

main menu
Fill “Share Host” and “Path to Image”

Confirmation when everything is OK

main menu
The confirmation of image on windows share has been successfully set.

Update supermicro server’s firmware BIOS under linux with the SUM cli

The newer Supermicro motherboards have the ability to update the system BIOS from IPMI Web management or with a Supermicro tool called

“Supermicro Update Manager (SUM)”

This tool consists of a linux cli and it works on most of the X9/X10/X11 Supermicro systems. If you have one of these motherboards you probably could update your BIOS under linux console and throwing away your freedos cd prehistoric update process (probably coming soon). If you’ve used Supermicro with for ages you probably are aware of the problem with the updating the BIOS, their tool is an old DOS flash utility, which could be used under MS Windows and with linux servers we got a problem! But not any more! Recent motherboards with built-in IPMI modules have “BIOS Update” option in the web interface (under Maintenance menu), but you need a license (which by the way is not expensive).

main menu
BIOS Update

So if you happen to have such server you could give a try to SUM linux cli (yes they made a linux cli and even a freebsd one!). With the SUM cli you could do more than just update the BIOS (which is pretty important) here are the functions you can do Key Management, System Checks, BIOS Management, BMC Management, System Event Log, CMM Management, Storage Management, Applications (through the network) and for some of them you still need a license, but for BIOS update you do not need if you do it as Supermicro says

In-Band

which basically means from the server you want to update (or in general use it). KEEP IN MIND this method will reset your BIOS options to DEFAULTS!!! In fact you need a license to use preserve settings you can see the output of the SUM help for the command UpdateBios. So save your changes to recover them after the update!
And here we present a BIOS update with SUM on one of our Supermicro servers with motherboard X11SSV-M4F
So the BIOS version was 1.0 reported by lshw:

[srv@local ~]# lshw|head -n 25
srv@local
    description: System
    product: Super Server (To be filled by O.E.M.)
    vendor: Supermicro
    version: 0123456789
    serial: 0123456789
    width: 64 bits
    capabilities: smbios-3.0 dmi-3.0 smp vsyscall32
    configuration: boot=normal chassis=server family=To be filled by O.E.M. sku=To be filled by O.E.M. uuid=00000000-0000-0000-0000-111111111111
  *-core
       description: Motherboard
       product: X11SSV-M4F
       vendor: Supermicro
       physical id: 0
       version: 1.02
       serial: 112233000044
       slot: To be filled by O.E.M.
     *-firmware
          description: BIOS
          vendor: American Megatrends Inc.
          physical id: 0
          version: 1.0
          date: 10/18/2016
          size: 64KiB
          capacity: 15MiB

And here are the steps to do:

STEP 1) Download the SUM cli – Supermicro Update Manager and unpack it in your server

You could download freely the SUM version 2 from here: https://www.supermicro.com/solutions/SMS_SUM.cfm (this link explains what the tool is used for) at the bottom of the page there is a link to download the SUM – https://www.supermicro.com/SwDownload/UserInfo.aspx?sw=0&cat=SUM Here you should fill the form with your name, company and email address and then you will be redirected to the download page, which at present is like the screenshot below:

main menu
Supermicro Update Manager (SUM)

When downloaded the linux version you would have the following files in the archive file:

[srv@local ~]# cd
[srv@local ~]# tar xzvf sum_2.0.0_Linux_x86_64_20171108.tar.gz
sum_2.0.0_Linux_x86_64/
sum_2.0.0_Linux_x86_64/ReleaseNote.txt
sum_2.0.0_Linux_x86_64/sum
sum_2.0.0_Linux_x86_64/ExternalData/
sum_2.0.0_Linux_x86_64/ExternalData/VENID.txt
sum_2.0.0_Linux_x86_64/ExternalData/SMCIPID.txt
sum_2.0.0_Linux_x86_64/driver/
sum_2.0.0_Linux_x86_64/driver/RHL4_x86_64/
sum_2.0.0_Linux_x86_64/driver/RHL4_x86_64/sum_bios.ko
sum_2.0.0_Linux_x86_64/driver/RHL6_x86_64/
sum_2.0.0_Linux_x86_64/driver/RHL6_x86_64/sum_bios.ko
sum_2.0.0_Linux_x86_64/driver/RHL5_x86_64/
sum_2.0.0_Linux_x86_64/driver/RHL5_x86_64/sum_bios.ko
sum_2.0.0_Linux_x86_64/driver/RHL7_x86_64/
sum_2.0.0_Linux_x86_64/driver/RHL7_x86_64/sum_bios.ko
sum_2.0.0_Linux_x86_64/SUM_UserGuide.pdf

The “sum” file binary is the tool you need.

STEP 2) Download the new motherboard BIOS firmware

, which for our board (X11SSV-M4F – https://www.supermicro.com/products/motherboard/Xeon/C236_C232/X11SSV-M4F.cfm) it was version 1.1 with filename “X11SVMF8_308.zip”, unpack the file under X11SVMF8_308

[srv@local ~]# cd
[srv@local ~]# unzip X11SVMF8_308.zip
Archive:  X11SVMF8_308.zip
   creating: X11SVMF8.308/
  inflating: X11SVMF8.308/AFUDOSU.SMC  
  inflating: X11SVMF8.308/CHOICE.SMC  
  inflating: X11SVMF8.308/FDT.smc    
  inflating: X11SVMF8.308/FLASH.BAT  
  inflating: X11SVMF8.308/Readme for UP X11 AMI  BIOS.txt  
  inflating: X11SVMF8.308/X11SVMF8.308

The file “X11SVMF8.308” is the BIOS firmware of the motherboard. As you can see the prehistoric DOS executable flash utility is still distributed and is supported method of updating.

STEP 3) Update the BIOS

[srv@local ~]# cd /root/sum_2.0.0_Linux_x86_64
[srv@local ~]# ./sum -c UpdateBios --file ../X11SVMF8.308/X11SVMF8.308 
Supermicro Update Manager (for UEFI BIOS) 2.0.0 (2017/11/08) (x86_64)
Copyright©2017 Super Micro Computer, Inc. All rights reserved
Reading BIOS flash ..................... (100%)
Checking BIOS ID ...
Checking ME Firmware ...
Comparing FDT for ROM file and flash.... (100%)

***************************<<<<<CRITICAL WARNING>>>>>***************************

ExitCode                = 254
Description             = Manual steps are required
Program Error Code      = 119.18
Error message:
    FDT is different. Please use system reboot(do not shutdown 
    or poweroff system) command to force ME enter manufacturing mode 
    and run UpdateBIOS command again to update BIOS and ME region.

********************************************************************************
[srv@local ~]# reboot

As you can see we got critical warning! You may not have the critical, but if you do you need to run the command second time to really flash the new BIOS firmware. So here it is, AFTER rebooting your server login again and execute the command again:

[srv@local ~]# cd /root/sum_2.0.0_Linux_x86_64
[srv@local ~]# ./sum -c UpdateBios --file ../X11SVMF8.308/X11SVMF8.308 
Supermicro Update Manager (for UEFI BIOS) 2.0.0 (2017/11/08) (x86_64)
Copyright©2017 Super Micro Computer, Inc. All rights reserved
Reading BIOS flash ..................... (100%)
Checking BIOS ID ...
Programming BIOS and ME (including FDT)
Writing BIOS flash ..................... (100%)
Verifying BIOS flash ................... (100%)
Checking ME Firmware ...
Putting ME data to BIOS ................ (100%)
Writing ME region in BIOS flash ...
 - Update success for FDR
 - Updated Recovery Loader to OPRx
 - Updated FPT, MFSB, FTPR and MFS
 - ME Entire Image done
WARNING:Must power cycle or restart the system for the changes to take effect!
[srv@local ~]# reboot

And there you have it you updated the BIOS of your server successfully. KEEP IN MIND the BIOS settings are reset to Defaults! When you restart the server the second time (if you get the critical warning or the first time if you do not) you should load the optimized defaults and change your settings according your needs. Go to BIOS and load the optimized defaults and change the settings according your needs (or your backup).

[srv@local ~]# lshw|head -n 25
srv@local
    description: System
    product: Super Server (To be filled by O.E.M.)
    vendor: Supermicro
    version: 0123456789
    serial: 0123456789
    width: 64 bits
    capabilities: smbios-3.0 dmi-3.0 smp vsyscall32
    configuration: boot=normal chassis=server family=To be filled by O.E.M. sku=To be filled by O.E.M. uuid=00000000-0000-0000-0000-111111111111
  *-core
       description: Motherboard
       product: X11SSV-M4F
       vendor: Supermicro
       physical id: 0
       version: 1.02
       serial: 112233000044
       slot: To be filled by O.E.M.
     *-firmware
          description: BIOS
          vendor: American Megatrends Inc.
          physical id: 0
          version: 1.1
          date: 03/08/2018
          size: 64KiB
          capacity: 15MiB

* SUM cli – UpdateBios help output

[srv@local ~]# ./sum -h -c UpdateBios
Supermicro Update Manager (for UEFI BIOS) 2.0.0 (2017/11/08) (x86_64)
Copyright©2017 Super Micro Computer, Inc. All rights reserved
Description
    Updates BIOS with the given image file.
Required Arguments
    --file    <file name>
Optional Arguments
    --reboot
          Forces the managed system to reboot or power up after operation.
    --flash_smbios
          Overwrites the SMBIOS data
    --preserve_nv
          Preserves the NVRAM region
    --preserve_mer
          Preserves the ME firmware region
    --preserve_setting
          Preserves setting configurations
Usage Modes
    [OOB] [In-Band] [Multiple systems OOB] 
Node Product Key Required
     No for [In-Band]
    Yes for [OOB]
Examples
OOB
  # ./sum -i 192.168.34.56 -u ADMIN -p ADMIN -c UpdateBios --file BIOS.rom 
    --reboot
In-Band
  # ./sum -c UpdateBios --file BIOS.rom --reboot
Multiple systems OOB
  # ./sum -l IP_ADDR_RANGE.txt -u ADMIN -p ADMIN -c UpdateBios --file BIOS.rom 
    --reboot
Notice
    1. For [OOB] and [Multiple systems OOB] usage modes, before executing this 
    command, it is recommended to shutdown the managed system first.
    2. --preserve_setting option is only supported in Purley and the platforms 
    of later versions. Note that --preserve_setting option for in-band usage 
    requires "SFT-OOB-LIC" product key. The preserved setting configurations 
    will be listed in preserved_settings.log.

* SUM cli generic help output


[srv@local ~]# ./sum 
Supermicro Update Manager (for UEFI BIOS) 2.0.0 (2017/11/08) (x86_64)
Copyright©2017 Super Micro Computer, Inc. All rights reserved

NAME
  sum (Supermicro Update Manager)

SYNOPSIS
  sum [OPTIONs] [COMMAND] [COMMAND ARGUMENTS]

OPTIONS
  -h  Shows help information.
  -v  Displays the verbose output.
  -i  <BMC/CMM IP address or BMC/CMM host name>
  -l  <BMC/CMM system list file name. Refer to the user's guide for formatting>
  -u  <BMC/CMM user ID>
  -p  <BMC/CMM user password>
  -c  <command name> (case insensitive)

USAGE MODES
○  Single System Out-Of-Band (OOB) Management [operates on single BMC/CMM]: 
    Must use -i,-u, -p options
○  Single System In-Band Management [operates on local OS]: Do not use -i, -u 
    and -p options
○  Concurrent Systems OOB Management [operates on multiple system BMCs/CMMs]: 
    Replace -i option with -l option

COMMANDS
Function Group             Command Names

Key Management             ActivateProductKey, QueryProductKey, ClearProductKey
System Checks              CheckOOBSupport, CheckAssetInfo, 
                           CheckSystemUtilization, CheckSensorData
BIOS Management            GetBIOSInfo, UpdateBios, GetDefaultBiosCfg, 
                           GetCurrentBiosCfg, ChangeBiosCfg, 
                           LoadDefaultBiosCfg, GetDmiInfo, ChangeDmiInfo, 
                           EditDmiInfo, SetBiosAction
BMC Management             GetBmcInfo, UpdateBmc, GetBmcCfg, ChangeBmcCfg
System Event Log           GetEventLog, ClearEventLog
CMM Management             GetCmmInfo, UpdateCmm, GetCmmCfg, ChangeCmmCfg
Storage Management         GetRaidControllerInfo, UpdateRaidController, 
                           GetRaidCfg, ChangeRaidCfg, GetSataInfo, GetNvmeInfo
Applications               TpmProvision, MountIsoImage, UnmountIsoImage

COMMAND USAGE
  See help message for each command
  Syntax:"  # ./sum -h -c <command name>"
  Notes: 1)Command support is platform dependent. Please refer to Appendix C in 
         the user's guide for platform dependency hints.
         2)If BMC/CMM user ID or password includes special characters, it has 
         to be quoted.

EXAMPLES
OOB
  # ./sum -i 192.168.34.56 -u ADMIN -p ADMIN -c ChangeBmcCfg --file BmcCfg.txt
  # ./sum -i 192.168.34.56 -u ADMIN -p "&123456" -c ChangeBmcCfg --file 
  BmcCfg.txt
Multiple systems OOB
  # ./sum -l IP_ADDR_RANGE.txt -u ADMIN -p ADMIN -c GetBIOSInfo --file BIOS.rom
  # ./sum -l IP_ADDR_RANGE.txt -u ADMIN -p "&123456" -c GetBIOSInfo --file 
  BIOS.rom
In-Band
  # ./sum -c UpdateBios --file BIOS.rom
Help Message
  # ./sum -h -c UpdateBios

grub2: grub-install: error: disk mduuid not found even after the partition has bios_grub on

This tutorial is for all of us that has done everything by the book with parted and still they receive an error when installing grub2 to the boot sector!

srv@local ~ # grub2-install /dev/sda
Installing for i386-pc platform.
grub2-install: error: disk `mduuid/51b39c2b565a6629d9efc9b3c39b44ff' not found. 

The solution is simple enough:

set the bios_grub on AGAIN even the parted reported it as ON

So you have a problem with your disks and booted to reinstall the grub and used parted from the rescue CD/DVD/USB and then you chroot to the OS you wanted to repair and execute

grub2-install or grub-install

you get the error above? But why parted reported this:

srv@local ~ # parted /dev/sda
GNU Parted 3.2
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) p                                                                
Model: DELL PERC H700 (scsi)
Disk /dev/sda: 480GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system     Name     Flags
 1      1049kB  2097kB  1049kB                  primary  bios_grub
 2      2097kB  4096MB  4094MB  linux-swap(v1)  primary  raid
 3      4096MB  24.0GB  19.9GB  ext4            primary
 4      24.0GB  480GB   456GB   ext4            primary

(parted)

And still you get the error:

grub2-install: error: disk `mduuid/51b39c2b565a6629d9efc9b3c39b44ff' not found. 

Why it is unknown for us, but the solution was simple, just do SET the flag again – in our case in the chrooted environment we used the parted program from the distro we wanted to repair and the grub-install was then used from the same distro (in the chrooted environment). At first we used the parted from the rescue distro, but apparently they are some issues with the versions even the two parted program – that one from the chrooted environment and from the rescue distro reported the bios_grub as set ON.
It is possible to get this error after using

sgdisk

to duplicate the partition table of a disk (BTW ALWAYS use “-G, –randomize-guids” with sgdisk, after you duplicate the partition table of a disk or you’ll get into BIG troubles!).
So to write down the solution (in fact it’s like a workaround):

srv@local ~ # parted /dev/sda
GNU Parted 3.2
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) set 1 bios_grub on
(parted) q
srv@local ~ # parted /dev/sdb
GNU Parted 3.2
Using /dev/sdb
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) set 1 bios_grub on
(parted) q
srv@local ~ # grub2-install /dev/sda
Installing for i386-pc platform.
Installation finished. No error reported.
srv@local ~ # grub2-install /dev/sdb
Installing for i386-pc platform.
Installation finished. No error reported.

* If you are using UEFI enabled boot you probably need more options for the grub installation

Something like that for the grub2 installation (but it is specific for your distro – the path for efi directory, just find it under /boot and put the right path – nothing special!):

grub-install --recheck --target=x86_64-efi --efi-directory=/boot/efi/ /dev/sda

distccd failed to exec with “No such file or directory”

And you think your compile box using distccd is ready you start emerge in your server/desktop/laptop and the first package is OK, the your emerge is using the distccd properly and the compilation is distributed to the compile box get compiled.
But just then another package gets a warning during build time:

distcc[9356] (dcc_build_somewhere) Warning: failed to distribute, running locally instead

So everything is back in your machine not in the compile box! And you find in the logs of the distccd compile box:

Apr 23 00:36:17 compile distccd[6177]: (dcc_execvp) ERROR: failed to exec x86_64-pc-linux-gnu-clang++: No such file or directory
Apr 23 00:36:17 compile distccd[12965]: (dcc_job_summary) client: 10.10.10.10:54946 COMPILE_ERROR exit:110 sig:0 core:0 ret:0 time:3492ms x86_64-pc-linux-gnu-clang++ ../../v8/src/accessors.cc
Apr 23 00:36:17 compile distccd[13490]: (dcc_job_summary) client: 10.10.10.10:54954 COMPILE_ERROR exit:110 sig:0 core:0 ret:0 time:1677ms x86_64-pc-linux-gnu-clang++ ../../v8/src/asmjs/asm-types.cc
Apr 23 00:36:18 compile distccd[6178]: (dcc_execvp) ERROR: failed to exec x86_64-pc-linux-gnu-clang++: No such file or directory
Apr 23 00:36:18 compile distccd[6097]: (dcc_job_summary) client: 10.10.10.10:54956 COMPILE_ERROR exit:110 sig:0 core:0 ret:0 time:2340ms x86_64-pc-linux-gnu-clang++ ../../v8/src/assembler.cc
Apr 23 00:37:22 compile distccd[6180]: (dcc_execvp) ERROR: failed to exec x86_64-pc-linux-gnu-clang++: No such file or directory
Apr 23 00:37:22 compile distccd[13307]: (dcc_job_summary) client: 10.10.10.10:54990 COMPILE_ERROR exit:110 sig:0 core:0 ret:0 time:1878ms x86_64-pc-linux-gnu-clang++ ../../v8/src/heap/incremental-marking-job.cc
Apr 23 00:37:23 compile distccd[6184]: (dcc_execvp) ERROR: failed to exec x86_64-pc-linux-gnu-clang++: No such file or directory
Apr 23 00:37:23 compile distccd[13719]: (dcc_job_summary) client: 10.10.10.10:54992 COMPILE_ERROR exit:110 sig:0 core:0 ret:0 time:2139ms x86_64-pc-linux-gnu-clang++ ../../v8/src/heap/incremental-marking.cc

Ahh you missed a package, then you emerge it fast with (assumed you used Gentoo, but the solution is valid for all distros)

[root@local ]# emerge -v sys-devel/clang sys-devel/clang-runtime

And start up the build process again (if Gentoo with emerge) and again the same situation? Again the same error, but you have the “x86_64-pc-linux-gnu-clang++” command and when you type x86_64-pc-linux-gnu-clang++ it executes properly! So what is the problem? The problem is that x86_64-pc-linux-gnu-clang++ is not in the current environment PATH:

compile ~ # whereis x86_64-pc-linux-gnu-clang++
x86_64-pc-linux-gnu-clang++: /usr/lib64/llvm/5/bin/x86_64-pc-linux-gnu-clang++

The solution is very simple just restart “distccd”. A trivial one, but could save you time next time! If you install a package, which is expected to be used with distccd restart distccd!!!

Under Getnoo:

compile ~ # /etc/init.d/distccd restart
 * Caching service dependencies ...
 * Stopping distccd ...  [ ok ]
 * Starting distccd ...  [ ok ]
compile ~ #

* You might get error for another file, check if it exists if not install it and then restart the distccd daemon, for example you could get error for any of these:

x86_64-pc-linux-gnu-addr2line
x86_64-pc-linux-gnu-elfedit
x86_64-pc-linux-gnu-gprof
x86_64-pc-linux-gnu-ar
x86_64-pc-linux-gnu-g++
x86_64-pc-linux-gnu-ld
x86_64-pc-linux-gnu-as
x86_64-pc-linux-gnu-g++-6.4.0
x86_64-pc-linux-gnu-ld.bfd
x86_64-pc-linux-gnu-c++
x86_64-pc-linux-gnu-g++-7.2.0
x86_64-pc-linux-gnu-ld.gold
x86_64-pc-linux-gnu-c++-6.4.0
x86_64-pc-linux-gnu-gcc
x86_64-pc-linux-gnu-libgcrypt-config
x86_64-pc-linux-gnu-c++-7.2.0
x86_64-pc-linux-gnu-gcc-6.4.0
x86_64-pc-linux-gnu-llvm-config
x86_64-pc-linux-gnu-c++filt
x86_64-pc-linux-gnu-gcc-7.2.0
x86_64-pc-linux-gnu-nm
x86_64-pc-linux-gnu-clang
x86_64-pc-linux-gnu-gcc-ar
x86_64-pc-linux-gnu-objcopy
x86_64-pc-linux-gnu-clang++
x86_64-pc-linux-gnu-gcc-nm
x86_64-pc-linux-gnu-objdump
x86_64-pc-linux-gnu-clang-5.0
x86_64-pc-linux-gnu-gcc-ranlib
x86_64-pc-linux-gnu-pcre-config
x86_64-pc-linux-gnu-clang++-5.0
x86_64-pc-linux-gnu-gcov
x86_64-pc-linux-gnu-pkg-config
x86_64-pc-linux-gnu-clang-cl
x86_64-pc-linux-gnu-gcov-6.4.0
x86_64-pc-linux-gnu-ranlib
x86_64-pc-linux-gnu-clang-cl-5.0
x86_64-pc-linux-gnu-gcov-7.2.0
x86_64-pc-linux-gnu-readelf
x86_64-pc-linux-gnu-clang-cpp
x86_64-pc-linux-gnu-gcov-dump
x86_64-pc-linux-gnu-size
x86_64-pc-linux-gnu-clang-cpp-5.0
x86_64-pc-linux-gnu-gcov-tool
x86_64-pc-linux-gnu-strings
x86_64-pc-linux-gnu-cpp
x86_64-pc-linux-gnu-gfortran
x86_64-pc-linux-gnu-strip
x86_64-pc-linux-gnu-cpp-6.4.0
x86_64-pc-linux-gnu-gfortran-6.4.0
x86_64-pc-linux-gnu-xml2-config
x86_64-pc-linux-gnu-cpp-7.2.0
x86_64-pc-linux-gnu-gfortran-7.2.0
x86_64-pc-linux-gnu-xslt-config
x86_64-pc-linux-gnu-curl-config
x86_64-pc-linux-gnu-gio-querymodules

Resume compilation of a packet from where it failed under Gentoo

Sometimes problems are too specific, but they can show us a path to look for a more general problem and its solution. There was a nasty bug in emerging Firefox package in Gentoo basically it compiled all the source and then it got an error from the build script, but all the source was compiled successfully! So the solution was just to manually install with

ebuild

the package and not to wait for the fix 😉 A good workaround.

But what if we have a big package, which failed during compilation

because of “out of ram” or “out of space” or a missing library, which the maintainer did not included in the dependencies. So tens of minutes or even hours of compilation (yes, there are still such packets like chromium) is wasted and we must start up from the beginning? No you can continue the current failed compilation from the exact point of failure using “ebuild”.
In our example we have a failed compilation of chromium with “out of memory”. We need the exact version of the package, scroll to your emerge command and copy the version, in our case it was: chromium-67.0.3377.1.ebuild
Here are the commands:

STEP 1) Continue compilation

[root@local ]# ebuild /usr/portage/www-client/chromium/chromium-67.0.3377.1.ebuild compile
>>> Existing ${T}/environment for 'chromium-67.0.3377.1' will be sourced.
>>> Run 'clean' to start with a fresh environment.
>>> Checking chromium-67.0.3377.1.tar.xz's mtime...
>>> WORKDIR is up-to-date, keeping...
 * checking ebuild checksums 😉 ...                                                                                                    [ ok ]
 * checking auxfile checksums 😉 ...                                                                                                   [ ok ]
 * checking miscfile checksums 😉 ...                                                                                                  [ ok ]
 * Checking for at least 3 GiB RAM ...                                                                                                  [ ok ]
 * Checking for at least 5 GiB disk space at "/var/tmp/portage/www-client/chromium-67.0.3377.1/temp" ...                                [ ok ]
>>> It appears that 'setup' has already executed for 'chromium-67.0.3377.1'; skipping.
>>> Remove '/var/tmp/portage/www-client/chromium-67.0.3377.1/.setuped' to force setup.
>>> It appears that 'unpack' has already executed for 'chromium-67.0.3377.1'; skipping.
>>> Remove '/var/tmp/portage/www-client/chromium-67.0.3377.1/.unpacked' to force unpack.
>>> It appears that 'prepare' has already executed for 'chromium-67.0.3377.1'; skipping.
>>> Remove '/var/tmp/portage/www-client/chromium-67.0.3377.1/.prepared' to force prepare.
>>> It appears that 'configure' has already executed for 'chromium-67.0.3377.1'; skipping.
>>> Remove '/var/tmp/portage/www-client/chromium-67.0.3377.1/.configured' to force configure.
>>> Compiling source in /var/tmp/portage/www-client/chromium-67.0.3377.1/work/chromium-67.0.3377.1 ...
ninja -v -j6 -l6 -C out/Release mksnapshot
ninja: Entering directory `out/Release'

As you can see in the output above an existing environment for ‘chromium-67.0.3377.1’ will be sourced.
Here the compilation continue from the last failed compilation script, it skipped multiple source dependencies.

STEP 2) Install the package

In fact two commands:

ebuild /usr/portage/www-client/chromium/chromium-67.0.3377.1.ebuild install
ebuild /usr/portage/www-client/chromium/chromium-67.0.3377.1.ebuild qmerge

The first command “install” will install the package in the working directory of the emerge process and then the second “qmerge” will install all the files of the package in the install directory to the live filesystem and will do some additional checks and modifications in your systems package database to install the package properly as if the emerge was used.

Delete millions of files slowly without loading the server

There a situations when we need to delete a great deal of files from our filesystem and if we just execute

rm -Rf

the server will surely get loaded and the service it provides will degrade! What if you cannot reformat the filesystem, because the server use it extensively, but you need to delete let’s say a couple of millions file from it? We can use find and usleep (in most linux distro this program is installed by an additional package). The idea is to delete files one by one tuning the pause between every delete. Here you can execute this command in the background or a screen:

find /mnt/storage/old/ -type f -exec echo {} \; -exec rm {} \; -exec usleep 200000 \;

usleep accepts microseconds, so 200000 microseconds are 0.2 seconds. You can tune it precisely with a step of just a microsecond. In the real world under the bash console we probably will use values of max 1/10 of a second around above 100000 microseconds. Execute the command and then watch your server load and tune.

  • usleep in CentOS 7 is installed with package “initscripts”, which is installed by default
  • usleep in Ubuntu is missing and probably won’t find any safe place to download a package to install, but it can be sort of replace with “sleep <floating_point_number>s”, GNU sleep could accept floating point number for the delay and when added “s” at the end it could sleep for a fractions of a seconds. So the command for the Ubuntu is slightly changed:
    find /mnt/storage/old/ -type f -exec echo {} \; -exec rm {} \; -exec sleep 0.2s \;
    
  • not GNU version of sleep require NUMBER, so the smallest sleep is only 1 second, which is too big for the purpose. Check your man manual to see if your system has GNU sleep command.