CloudBlue knowledgebase (KB) CloudBlue knowledgebase (KB) en Copyright 2018 CloudBlue Wed, 10 Sep 2008 00:00:00 +0600 Wed, 10 Sep 2008 00:00:00 +0600 <![CDATA[Webspace http logs are not updated: Error on communication with redis: READONLY You can't write against a read only slave.]]> Symptoms

Apache log files are not getting updates for webspaces hosted on NG web server.

The following error is logged to /var/log/messages continuously:

Feb 10 10:49:51 ngweb1 /usr/sbin/log-dumper[548274]: Error on communication with redis: READONLY You can't write against a read only slave.

Another symptom of the problem can be failed "Creating virtual host directory structure" tasks with the output of:

User 'eXXXXXXX' does not exist


redis package has been updated on the NG web host(s) from a foreign repository to higher version that supported, which also could bring the read-only configuration.

[root@ngweb1 ~]# yum info redis
Loaded plugins: fastestmirror, rhnplugin, security
Loading mirror speeds from cached hostfile
 * cloudlinux-x86_64-server-6:
 * epel:
Installed Packages
Name        : redis
Arch        : x86_64
Version     : 3.2.11
Repo        : epel

[root@ngweb1 ~]# grep read-only /etc/redis.conf
# Since Redis 2.6 by default slaves are read-only.
slave-read-only yes

This may occur if Cloudlinux updates enabled imunify360 repository automatically (/etc/yum.repos.d/cloudlinux-imunify360.repo).


1. Disable all foreign repositories, the only YUM repos to be left are:


2. Downgrade redis package:

# yum downgrade redis

3. Stop Redis

# service redis stop

4. Delete or move RDB dump from /var/lib/redis/

5. In PCP > Infrastructure > Service Nodes > node_name > 'General' tab press Sync data to redis button

6. Wait for Dump webspace data to redis task to finish.

7. Start Redis

# service redis start

Please be aware that Redis shutdown causes downtime of customers' websites. Please also make sure /etc/redis.conf file does not contain slave-read-only setting set to "yes" afterwards.

41234 LastUpdated: 2018-11-26 11:12:16 10 Feb 2016 12:36:33 GMT