if you get the below error 

Access Denied

Unable to establish a PHP session.

The account must be able to write to the php session directory and must not exceed the assigned disk quota.

If you believe that this is in error or inadvertent, contact your system administrator and ask them to review your server settings.
Please check using following step 

2. Check the permission and ownership of /home/$user/tmp folder. Set ownership as $user.

# chown $user:$user /home/$user/tmp

3. Set permission of the tmp folder to 755.

#chmod -R 755 /home/$user/tmp

4. Test now to see if  PHPMyAdmin  is working fine now…if the answer is no, go to next step….

5.Check to see if there is a file like /var/cpanel/overquota/blocks_$user and removed it.

6. rm /var/cpanel/overquota/blocks_$user

We had a issue in one of the virtualizor node

Where the server on rebooting the KVM VM were not starting

With error message being

error: Failed to create domain from /etc/libvirt/qemu/
error: Cannot get interface MTU on ‘viifbr0’: No such device

ON checking around found the issue with virtnetwork

Below command fixed the issue

service virtnetwork start

~]# service virtnetwork start
Bringing up viifbr0 – OK
Waiting for 10 seconds…1…2…3…4…5…6…7…8…9…10
Internet connectivity check successful viifbr0 – OK

Below are the commands which are to be used in centos 7 to open port 80

[root@onlinesupport ~]# firewall-cmd --permanent --zone=public --add-port=80/tcp success 

[root@onlinesupport]# firewall-cmd --reload

While upgrading mysql in server make sure you make a backup of existing mysql

using commmand mysqldump --all-databases > all_databases.sql

Once you have complete backup , You can proceed with with upgrade of mysql.

Was having an issue where /tmp was getting 100% full every few minutes

on investigation i see the files of 3Gb over there in /tmp

#sql_436_0.MAD

ddvps20 tmp]# ls -al
total 3779332
drwxrwxrwt 12 root root 4096 Sep 21 10:24 .
dr-xr-xr-x 21 root root 4096 Sep 21 09:17 ..
drwxrwxrwt 2 root root 4096 Sep 21 09:17 .font-unix
drwxr-xr-x 2 cpanelsolr cpanelsolr 4096 Sep 21 10:22 hsperfdata_cpanelsolr
drwxr-xr-x 2 root root 4096 Sep 21 10:21 hsperfdata_root
drwxrwxrwt 2 root root 4096 Sep 21 09:17 .ICE-unix
drwx—— 2 root root 16384 Sep 21 09:56 lost+found
lrwxrwxrwx 1 root root 30 Sep 21 10:23 mysql.sock -> ../../var/lib/mysql/mysql.sock
-rw——- 1 cpdigita cpdigita 4096 Sep 21 10:11 .spamassassin1694OHMO4Dtmp
-rw——- 1 cpdigita cpdigita 0 Sep 21 10:17 .spamassassin1694voSq6Ctmp
-rw——- 1 cpdigita cpdigita 0 Sep 21 10:11 .spamassassin1694y0CJyjtmp
-rw——- 1 cpdigita cpdigita 0 Sep 21 10:04 .spamassassin18453ZHMaRtmp
-rw——- 1 cpdigita cpdigita 0 Sep 21 10:06 .spamassassin1845bypIDCtmp
-rw——- 1 cpdigita cpdigita 0 Sep 21 10:03 .spamassassin1845pCtlHqtmp
-rw-rw—- 1 mysql mysql 3866185728 Sep 21 10:07 #sql_436_0.MAD
-rw-rw—- 1 mysql mysql 8192 Sep 21 10:00 #sql_436_0.MAI
-rw——- 1 cpanelsolr cpanelsolr 165 Sep 21 10:22 start_2180387910403356223.properties
drwx—— 3 root root 4096 Sep 21 09:17 systemd-private-1d4af49159364e018772426d7df23a9d-named.service-8XVCsj
drwx—— 3 root root 4096 Sep 21 09:17 systemd-private-1d4af49159364e018772426d7df23a9d-named.service-FyUDBs
drwxrwxrwt 2 root root 4096 Sep 21 09:17 .Test-unix
drwxrwxrwt 2 root root 4096 Sep 21 09:17 .X11-unix
drwxrwxrwt 2 root root 4096 Sep 21 09:17 .XIM-unix

So mysql was going down due to /tmp being full

So as a work around found a better solution

To change the /tmp file to something else for mysql

vi /etc/my.cnf

tmpdir=/mysqltmp

Save the file with :wq

2. Create the /mysqltmp directory

mkdir /mysqltmp
chmod 1777 /mysqltmp



3. Restart MySQL and check that the tmpdir is now /mysqltmp

/etc/init.d/mysql restart
mysqladmin var | grep tmpdir

You should see the following return:

# mysqladmin var | grep tmpdir
| slave_load_tmpdir                       | /mysqltmp
| tmpdir                                  | /mysqltmp

yum install ImageMagick-devel ImageMagick-c++-devel ImageMagick-perl

/usr/bin/convert --version

/opt/cpanel/ea-php56/root/usr/bin/pecl install imagick

Was getting below error while trying to create mysql user in cpanel

Error from MySQL query :(XID 5yuvwf) The system received an error from the “MySQL” database “mysql”: 1805 (Column count of mysql.user is wrong. Expected 43, found 39. The table is probably corrupted):

The migration used a “mysqldump –all-databases” so it included the “mysql” database. Apparently the “mysql.proc” table changed between the versions. The fix on the new server is to run:

Below command fixed the issue