Category: General Computing

OK, so this was something I needed to do with CentOS 6: https://vivithemage.com/2014/08/08/centos-6-multiple-vlans-with-one-eth-device/

This is how to do it in CentOS 7. There are some slight changes required compared to CentOS 6, but they’re nominal. It’s possible it will work for CentOS 8, but it is untested. Where there is a command like vi bla/bla/file you will enter the following information in the line.

vi /etc/sysctl.conf
net.ipv4.ip_forward = 1
net.ipv4.conf.default.accept_source_route = 1
net.ipv4.conf.all.accept_source_route = 1

cd /etc/sysconfig/network-scripts/

vi ifcfg-em1
TYPE=Ethernet
DEVICE=em1
BOOTPROTO=none
ONBOOT=yes

vi ifcfg-em1.29
DEVICE=em1.29
BOOTPROTO=none
ONBOOT=yes
IPADDR=192.119.161.2
PREFIX=24
NETWORK=192.119.161.0
GATEWAY=192.119.161.1
VLAN=yes
ARPCHECK=no
NM_CONTROLLED=no

vi ifcfg-em1.33
DEVICE=em1.33
BOOTPROTO=none
ONBOOT=yes
IPADDR=192.119.165.2
PREFIX=24
GATEWAY=192.119.165.1
NETWORK=192.119.165.0
VLAN=yes
ARPCHECK=no
NM_CONTROLLED=no

vi ifcfg-em1.35
DEVICE=em1.35
BOOTPROTO=none
ONBOOT=yes
IPADDR=192.119.167.2
PREFIX=24
NETWORK=192.119.167.0
GATEWAY=192.119.167.1
VLAN=yes
ARPCHECK=no
NM_CONTROLLED=no

vi ifcfg-em1.29-range
IPADDR_START=192.119.161.3
IPADDR_END=192.119.161.254
PREFIX=24
CLONENUM_START=3
ARPCHECK=no

vi ifcfg-em1.33-range
IPADDR_START=192.119.165.3
IPADDR_END=192.119.165.254
NETMASK=255.255.255.0
CLONENUM_START=254
ARPCHECK=no

vi ifcfg-em1.35-range
IPADDR_START=192.119.167.3
IPADDR_END=192.119.167.254
NETMASK=255.255.255.0
CLONENUM_START=506
ARPCHECK=no

echo ‘default via 192.119.161.1 dev em1.29 table 1’ > route-em1.29
echo ‘default via 192.119.165.1 dev em1.33 table 2’ > route-em1.33
echo ‘default via 192.119.167.1 dev em1.35 table 3’ > route-em1.35
echo ‘from 192.119.161.2 tab 1 priority 500’ > rule-em1.29
echo ‘from 192.119.165.2 tab 2 priority 501’ > rule-em1.33
echo ‘from 192.119.167.2 tab 3 priority 502’ > rule-em1.35
echo ‘from 192.119.161.0/24 table 1’ >> rule-em1.29
echo ‘from 192.119.165.0/24 table 2’ >> rule-em1.33
echo ‘from 192.119.167.0/24 table 3’ >> rule-em1.35

THIS WORKS FOR TESTING

ip route add default via 192.119.161.1 dev em1.29 table 1
ip route add default via 192.119.165.1 dev em1.33 table 2
ip route add default via 192.119.167.1 dev em1.35 table 3
ip rule add from 192.119.161.2 tab 1 priority 500
ip rule add from 192.119.165.2 tab 2 priority 501
ip rule add from 192.119.167.2 tab 3 priority 502
ip rule add from 192.119.161.0/24 table 1
ip rule add from 192.119.165.0/24 table 2
ip rule add from 192.119.167.0/24 table 3

THIS IS REQUIRED TO PING DURING TEST – THIS ONE WIL NOT SUSTAIN REBOOT

ip route add default via 198.50.31.1

## THIS WILL SUSTAIN REBOOT – ONLY NEEDED FOR TESTING

echo 'default via 198.50.31.1' > route-em1.15

### END TESTING STUFFS

My back up server uses keys, and SSH to allow for backups. By default, in my cPanel server running CENTOS 7.7 with v86.0.18 of cPanel, you really only have the option to do a path related to the SSH user’s home log in directory. My back up server has a mount point outside of /home/user/ so I needed to find a way to force it to go to /data/madhost613/ as an example.

Once you create your SFTP back up options under “backup settings” in the cPanel GUI, you can create an “additional destinations”. This will allow your back ups to be sent somewhere else.

I would advise using key based authentication when you set up SFTP as a destination. It is far more secure then password based authentication. Once you set up your SFTP and have validated it, SSH into your SOURCE server running cPanel to make the change to the validation configuration file. It should be in: /var/cpanel/backups/ The file itself will look simliar to this: backups_link_data_drive_UID_vxxxxxxxxxxxxxxxxxxxxxx Once you found it, edit it with your favorite editor. Which should be vi ;). In that configuration file is a path line, go ahead and modify it to your aboslute path. Mine now reads: path: /data/madhost613/ Some caveats with this, the SSH user must have r/w on that destination server. Once you make this change, you can run the validation in cPanel, and if successful, your back ups will be sent to that directory now.

cPanel informed me this should be an added feature at some point, but currently unknown when. But this work around works fine.

I am shamelessly stealing this from: https://fsfe.soup.io/post/651104763/Evaggelos-Balaskas-System-Engineer-CentOS-Dist-Upgrade

I wanted to keep this information around if their site goes tits up. I did this on a newly installed Cent OS 6.10 upgrade as of this morning and it worked fine. I had not tried it with odd packages installed, or abnormally outdated packages, so your mileage may vary. Good luck, and as always, no one “supports” this procedure, the best option to upgrade is a CLEAN install to CENTOS 8. At this point 8 is tried and true and will keep your server supported longer.

PRE TASKS

There are some tasks you can do to prevent from unwanted results. Like:

• Disable selinux
• Remove unnecessary repositories
• Take a recent backup!

CENTOS UPGRADE REPOSITORY

Create a new centos repository:

cat > /etc/yum.repos.d/centos-upgrade.repo <<EOF
[centos-upgrade]
name=centos-upgrade
baseurl=https://buildlogs.centos.org/centos/6/upg/x86_64/
enabled=1
gpgcheck=0
EOF

INSTALL PRE-UPGRADE TOOL

First install the openscap version from dev.centos.org:

# yum -y install https://buildlogs.centos.org/centos/6/upg/x86_64/Packages/openscap-1.0.8-1.0.1.el6.centos.x86_64.rpm

then install the redhat upgrade tool:

# yum -y install redhat-upgrade-tool preupgrade-assistant-*

IMPORT CENTOS 7 PGP KEY

# rpm --import http://mirror.centos.org/centos/7/os/x86_64/RPM-GPG-KEY-CentOS-7

NOTE:

to bypass errors like:

Downloading failed: invalid data in .treeinfo: No section: ‘checksums’

append CentOS Mirror under mirrorlist:

mkdir -pv /var/tmp/system-upgrade/base/ /var/tmp/system-upgrade/extras/ /var/tmp/system-upgrade/updates/

echo http://mirror.centos.org/centos/7/os/x86_64/ >> /var/tmp/system-upgrade/base/mirrorlist.txt
echo http://mirror.centos.org/centos/7/extras/x86_64/ >> /var/tmp/system-upgrade/extras/mirrorlist.txt
echo http://mirror.centos.org/centos/7/updates/x86_64/ >> /var/tmp/system-upgrade/updates/mirrorlist.txt

PRE-UPGRADE

preupg is actually a python script!

# yes | preupg -v
Preupg tool doesn't do the actual upgrade.
Please ensure you have backed up your system and/or data in the event of a failed upgrade
that would require a full re-install of the system from installation media.
Do you want to continue? y/n
Gathering logs used by preupgrade assistant:
All installed packages : 01/11 ...finished (time 00:00s)
All changed files : 02/11 ...finished (time 00:18s)
Changed config files : 03/11 ...finished (time 00:00s)
All users : 04/11 ...finished (time 00:00s)
All groups : 05/11 ...finished (time 00:00s)
Service statuses : 06/11 ...finished (time 00:00s)
All installed files : 07/11 ...finished (time 00:01s)
All local files : 08/11 ...finished (time 00:01s)
All executable files : 09/11 ...finished (time 00:01s)
RedHat signed packages : 10/11 ...finished (time 00:00s)
CentOS signed packages : 11/11 ...finished (time 00:00s)
Assessment of the system, running checks / SCE scripts:
001/096 ...done (Configuration Files to Review)
002/096 ...done (File Lists for Manual Migration)
003/096 ...done (Bacula Backup Software)
...
./result.html
/bin/tar: .: file changed as we read it
Tarball with results is stored here /root/preupgrade-results/preupg_results-180508202952.tar.gz .
The latest assessment is stored in directory /root/preupgrade .
Summary information:
We found some potential in-place upgrade risks.
Read the file /root/preupgrade/result.html for more details.
Upload results to UI by command:
e.g. preupg -u http://127.0.0.1:8099/submit/ -r /root/preupgrade-results/preupg_results-*.tar.gz .
this must finish without any errors.

CENTOS UPGRADE TOOL

We need to find out what are the possible problems when upgrade:

# centos-upgrade-tool-cli --network=7 --instrepo=http://vault.centos.org/7.0.1406/os/x86_64/

Then by force we can upgrade to it’s latest version:

# centos-upgrade-tool-cli --force --network=7 --instrepo=http://vault.centos.org/7.0.1406/os/x86_64/ --cleanup-post

Output:

setting up repos...
base | 3.6 kB 00:00
base/primary_db | 4.9 MB 00:04
centos-upgrade | 1.9 kB 00:00
centos-upgrade/primary_db | 14 kB 00:00
cmdline-instrepo | 3.6 kB 00:00
cmdline-instrepo/primary_db | 4.9 MB 00:03
epel/metalink | 14 kB 00:00
epel | 4.7 kB 00:00
epel | 4.7 kB 00:00
epel/primary_db | 6.0 MB 00:04
extras | 3.6 kB 00:00
extras/primary_db | 4.9 MB 00:04
mariadb | 2.9 kB 00:00
mariadb/primary_db | 33 kB 00:00
remi-php56 | 2.9 kB 00:00
remi-php56/primary_db | 229 kB 00:00
remi-safe | 2.9 kB 00:00
remi-safe/primary_db | 950 kB 00:00
updates | 3.6 kB 00:00
updates/primary_db | 4.9 MB 00:04
.treeinfo | 1.1 kB 00:00
getting boot images...
vmlinuz-redhat-upgrade-tool | 4.7 MB 00:03
initramfs-redhat-upgrade-tool.img | 32 MB 00:24
setting up update...
finding updates 100% [=========================================================]
(1/323): MariaDB-10.2.14-centos6-x86_64-client.rpm | 48 MB 00:38
(2/323): MariaDB-10.2.14-centos6-x86_64-common.rpm | 154 kB 00:00
(3/323): MariaDB-10.2.14-centos6-x86_64-compat.rpm | 4.0 MB 00:03
(4/323): MariaDB-10.2.14-centos6-x86_64-server.rpm | 109 MB 01:26
(5/323): acl-2.2.51-12.el7.x86_64.rpm | 81 kB 00:00
(6/323): apr-1.4.8-3.el7.x86_64.rpm | 103 kB 00:00
(7/323): apr-util-1.5.2-6.el7.x86_64.rpm | 92 kB 00:00
(8/323): apr-util-ldap-1.5.2-6.el7.x86_64.rpm | 19 kB 00:00
(9/323): attr-2.4.46-12.el7.x86_64.rpm | 66 kB 00:00
...
(320/323): yum-plugin-fastestmirror-1.1.31-24.el7.noarch.rpm | 28 kB 00:00
(321/323): yum-utils-1.1.31-24.el7.noarch.rpm | 111 kB 00:00
(322/323): zlib-1.2.7-13.el7.x86_64.rpm | 89 kB 00:00
(323/323): zlib-devel-1.2.7-13.el7.x86_64.rpm | 49 kB 00:00
testing upgrade transaction
rpm transaction 100% [=========================================================]
rpm install 100% [=============================================================]
setting up system for upgrade
Finished. Reboot to start upgrade.

REBOOT

The upgrade procedure, will download all rpm packages to a directory and create a new grub entry. Then on reboot the system will try to upgrade the distribution release to it’s latest version.

# reboot