Occasionally, you might get this message when you go to your favorite WordPress blog–especially if you have a load-balanced, distributed web server, like this one. I have a couple of Raspberry PIs, running apache, that are front-ended with HAProxy. When I start a plugin update on my site, that activity is run by one of the Raspberries. It completes just fine, but the completion test gets run by another Raspberry and loses the continuity and things don’t get cleaned up properly, especially the maintenance mode! Fret not! This is simple to fix.
ssh into your web server and go to the website root directory. The default is /var/www/html. This is a shared mount on my gang of Raspberries that points to a NAS mounted directory. Get a directory listing with all files and you will quickly see the culprit:
[root@rock howto]# ls -la total 3336 drwxr-xr-x 5 www-data www-data 4096 May 1 09:05 . drwxr-xr-x. 12 www-data www-data 209 Apr 28 12:14 .. -rw-r--r-- 1 root root 3188815 Apr 29 09:37 howto.sql -rw-r--r-- 1 www-data www-data 405 Apr 18 16:12 index.php -rw-r--r-- 1 www-data www-data 19915 Apr 18 16:13 license.txt -rw-r--r-- 1 www-data 33 33 May 1 08:58 .maintenance -rw-r--r-- 1 www-data www-data 7278 Apr 29 18:15 readme.html -rw-r--r-- 1 www-data www-data 2882 Apr 18 16:13 sample -rw-r--r-- 1 www-data www-data 6912 Apr 18 16:13 wp-activate.php drwxr-xr-x 9 www-data www-data 4096 Apr 24 09:12 wp-admin -rw-r--r-- 1 www-data www-data 351 Apr 18 16:13 wp-blog-header.php -rw-r--r-- 1 www-data www-data 2275 Apr 18 16:13 wp-comments-post.php -rw-r--r-- 1 www-data www-data 3187 Apr 20 13:03 wp-config.php -rw-r--r-- 1 www-data www-data 2913 Apr 18 16:13 wp-config-sample.php drwxr-xr-x 6 www-data www-data 106 May 1 09:00 wp-content -rw-r--r-- 1 www-data www-data 3940 Apr 18 16:15 wp-cron.php drwxr-xr-x 21 www-data www-data 8192 Apr 20 13:02 wp-includes -rw-r--r-- 1 www-data www-data 2496 Apr 18 16:15 wp-links-opml.php -rw-r--r-- 1 www-data www-data 3300 Apr 18 16:15 wp-load.php -rw-r--r-- 1 www-data www-data 47874 Apr 18 16:15 wp-login.php -rw-r--r-- 1 www-data www-data 8509 Apr 29 18:15 wp-mail.php -rw-r--r-- 1 www-data www-data 19396 Apr 29 18:15 wp-settings.php -rw-r--r-- 1 www-data www-data 31111 Apr 18 16:15 wp-signup.php -rw-r--r-- 1 www-data www-data 4755 Apr 18 16:15 wp-trackback.php -rw-r--r-- 1 www-data www-data 3133 Apr 18 16:15 xmlrpc.php [root@rock howto]#rm .maintenance
Just delete the .maintenance hidden file and you’re up-and-running again!