[Dovecot] Ring SYNC appears to have got lost, resending after upgrade

[/dev/rob0]

On Mon, Sep 09, 2013 at 11:13:36AM +0200, Patrick Westenberg wrote:
> on Saturday I upgraded two dovecot servers from squeeze to wheezy 
> and dovecot from 2.1.x to 2.2.5 (compiled from sources). After the 
> upgrade everything worked fine at first.
> 
> On Sunday Morning I recognized these errors (they occured after a
> reload for logging purpose on midnight) on one server:
> 
> director: Error: Ring SYNC appears to have got lost, resending
> 
> After reloading/restarting both dovecot services the error occured 
> on both servers. After some research I deleted some "zlib"-File 
> which isn't needed anymore in dovecot 2.2.x and reinstalled 
> dovecot. The error message disappeared.
> 
> Today the error occured again (after the reload on midnight) and 
> again on one node only until reloading/restarting the other node 
> too. However, there is an additional error message:
> 
> Sep 09 10:27:07 director: Error: Ring SYNC appears to have got 
> lost, resending
> Sep 09 10:27:10 director: Panic: file login-connection.c: line 88
> (login_host_callback): assertion failed: (strncmp(request->line,
> "OK\t", 3) == 0)

I had the same issue (CentOS 6.4 upgraded with third-party RPMs) on 
Thu/Fri, and I asked Timo about it in IRC. Apparently a 2.2.6 release 
is due soon. He gave me two hg links claimed to fix it:

http://hg.dovecot.org/dovecot-2.2/rev/f7a37b169f4a 
http://hg.dovecot.org/dovecot-2.2/rev/9531ec8afe8b

However I did have the lost ring SYNC error recur after the cluster 
was upgraded to the RPM packages currently in Dovecot's EE repo 
(non-free, pay for access) which does include these fixes.

Restart of all director instances worked for me. Actually I stopped 
all, then started all.

So far so good. We're going to go live with this cluster soon, I 
hope.


> node1:
> # 2.2.5: /usr/local/etc/dovecot/dovecot.conf
> # OS: Linux 3.2.0-4-amd64 x86_64 Debian 7.1
> auth_mechanisms = plain login
> director_mail_servers = 172.17.1.2 172.17.1.1
> director_servers = 172.17.1.3 172.17.1.4
> director_user_expire = 5 mins
> lmtp_proxy = yes
> log_path = /var/log/dovecot.log
> managesieve_notify_capability = mailto
> managesieve_sieve_capability = fileinto reject envelope
> encoded-character vacation subaddress comparator-i;ascii-numeric
> relational regex imap4flags copy include variables body enotify
> environment mailbox date ihave
> protocols = imap pop3 lmtp sieve
> service auth {
>   unix_listener /var/spool/postfix/private/auth {
>     group = postfix
>     mode = 0666
>     user = postfix
>   }
>   unix_listener auth-userdb {
>     user = dovecot
>   }
> }
> service director {
>   fifo_listener login/proxy-notify {
>     mode = 0666
>   }
>   inet_listener {
>     address = 172.17.1.3
>     port = 9090
>   }
>   unix_listener director-userdb {
>     mode = 0600
>   }
>   unix_listener login/director {
>     mode = 0666
>   }
> }
> service imap-login {
>   executable = imap-login director
> }
> service lmtp {
>   inet_listener lmtp {
>     address = 172.17.1.3
>     port = 24
>   }
> }
> service managesieve-login {
>   executable = managesieve-login director
>   inet_listener sieve {
>     port = 4190
>   }
> }
> service pop3-login {
>   executable = pop3-login director
> }
> ssl_cert = </etc/ssl/certs/wildcard.xxx.crt
> ssl_key = </etc/ssl/private/wildcard.xxx.key
> protocol !smtp {
>   passdb {
>     args = proxy=y nopassword=y starttls=any-cert
>     driver = static
>   }
> }
> protocol smtp {
>   passdb {
>     args = /usr/local/etc/dovecot/dovecot-sql.conf.ext
>     driver = sql
>   }
>   userdb {
>     args = /usr/local/etc/dovecot/dovecot-sql.conf.ext
>     driver = sql
>   }
> }
> protocol lmtp {
>   auth_socket_path = director-userdb
> }
> 
> 
> node2:
> # 2.2.5: /usr/local/etc/dovecot/dovecot.conf
> # OS: Linux 3.2.0-4-amd64 x86_64 Debian 7.1
> auth_mechanisms = plain login
> director_mail_servers = 172.17.1.2 172.17.1.1
> director_servers = 172.17.1.4 172.17.1.3
> director_user_expire = 5 mins
> lmtp_proxy = yes
> log_path = /var/log/dovecot.log
> managesieve_notify_capability = mailto
> managesieve_sieve_capability = fileinto reject envelope
> encoded-character vacation subaddress comparator-i;ascii-numeric
> relational regex imap4flags copy include variables body enotify
> environment mailbox date ihave
> protocols = imap pop3 lmtp sieve
> service auth {
>   unix_listener /var/spool/postfix/private/auth {
>     group = postfix
>     mode = 0666
>     user = postfix
>   }
>   unix_listener auth-userdb {
>     user = dovecot
>   }
> }
> service director {
>   fifo_listener login/proxy-notify {
>     mode = 0666
>   }
>   inet_listener {
>     address = 172.17.1.4
>     port = 9090
>   }
>   unix_listener director-userdb {
>     mode = 0600
>   }
>   unix_listener login/director {
>     mode = 0666
>   }
> }
> service imap-login {
>   executable = imap-login director
>   process_min_avail = 2
>   service_count = 0
>   vsz_limit = 128 M
> }
> service lmtp {
>   inet_listener lmtp {
>     address = 172.17.1.4
>     port = 24
>   }
> }
> service managesieve-login {
>   executable = managesieve-login director
>   inet_listener sieve {
>     port = 4190
>   }
> }
> service pop3-login {
>   executable = pop3-login director
> }
> ssl_cert = </etc/ssl/certs/wildcard.xxx.crt
> ssl_key = </etc/ssl/private/wildcard.xxx.key
> protocol !smtp {
>   passdb {
>     args = proxy=y nopassword=y starttls=any-cert
>     driver = static
>   }
> }
> protocol smtp {
>   passdb {
>     args = /usr/local/etc/dovecot/dovecot-sql.conf.ext
>     driver = sql
>   }
>   userdb {
>     args = /usr/local/etc/dovecot/dovecot-sql.conf.ext
>     driver = sql
>   }
> }
> protocol lmtp {
>   auth_socket_path = director-userdb
> }
> 

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