Fail2ban and logrotations

[StephenAtty]

Environment:

• Fail2Ban version (including any possible distribution suffixes): Fail2Ban v0.11.0.dev0
• OS, including release name/version: Ubuntu 14.04.5 LTS
• Fail2Ban installed via OS/distribution mechanisms
• You have not applied any additional foreign patches to the codebase
• Some customizations were done to the configuration (provide details below is so)

The issue:

Fail2ban writes into /var/log/fail2ban.log
Log rotate runs and changes the log files so that the old log is fail2ban.log.1
and the current log should be fail2ban.log

What seems to be happening is that logrotate changes the filename to fail2ban.log.1 but fail2ban continues to write into that log rather than using the new one...

-rw-r----- 1 root      adm             0 Oct  1 06:28 fail2ban.log
-rw-r--r-- 1 root      root        67859 Oct  1 12:59 fail2ban.log.1

Here is my logrotate configuration

/var/log/fail2ban.log {

    weekly
    rotate 4
    compress

    delaycompress
    missingok
    postrotate
        fail2ban-client set logtarget /var/log/fail2ban.log >/dev/null
    endscript

    # If fail2ban runs as non-root it still needs to have write access
    # to logfiles.
    # create 640 fail2ban adm
    create 640 root adm
}

[sebres]

Please take a look in our rotate-script:
https://github.com/fail2ban/fail2ban/blob/0.11/files/fail2ban-logrotate#L12

I assume following will help:

postrotate
-        fail2ban-client set logtarget /var/log/fail2ban.log >/dev/null
+        fail2ban-client flushlogs >/dev/null || true