[ClusterLabs] Antw: [EXT] Is 20 seconds to complete redis switchover to be expected?

[Ulrich Windl]

>>> steven prothero <steven at marimo-tech.com> schrieb am 31.03.2020 um 08:27 in
Nachricht
<25845_1585636109_5E82E30C_25845_727_1_CAJ7kUSOdWJUG9U+nDZRfw_jekpv6U2TTuPqJrDGK
hqQ9Z8OTw at mail.gmail.com>:
> Hello,
> 
> I am new with Pacemaker (new to redis also) and appreciate the info shared 
> here.
> 
> I believe with Redis sentinel  a switchover is about 2 seconds.
> Reading a post about Pacemaker with Redis, the author said he was
> doing it in 3 seconds.  For me, it takes about 20 seconds and I am
> wondering what I am doing wrong.
> 
> Example timeline from looking at the logs:
> 
> :00 ‑ node1 crash (redis‑server killed)
> :02 ‑ Pacemaker knows there is a problem.
> :02 ‑ STONITH/fence starts.  (fence_ipmilan power off)
> :09 ‑ STONITH/fence finished.
> :18 ‑ Redis switched.
> :19 ‑ VIP switched.

Obviously the logs between :02 and :18 would be most interesting...

> 
> During the time of the stonith/ fencing action nothing else is
> happening. It is the fence_ipmilan which does a poweroff. Can the
> fencing be started on node1 while node2 works in parallel to take care
> of the redis & VIP?   Also, after the stonith/fence is finished for 9
> seconds or so it is just pacemaker trying to invite the dead node1
> back (I think).  Be great if I could skip that and go directly to
> redis switch & vip switchovers.
> 
> I have been researching & testing with various configurations and
> would appreciate any pointers and advice.
> 
> I am using pacemaker 1.1.10, with 2 nodes.
> 
> my (edited) crm configure show :
> 
> node $id="1" example1.com \
>         attributes standby="off"
> node $id="2" example2.com
> primitive fence_example1 stonith:fence_ipmilan \
>         params pcmk_host_list="example1.com" ipaddr="10.24.x.xxx"
> login="user" passwd="password" pcmk_action_limit="‑1"
> concurrent‑fencing="true" lanplus="true" action="off" \
>         op monitor interval="20s" \
>         meta target‑role="Started"
> primitive fence_example2 stonith:fence_ipmilan \
>         params pcmk_host_list="example2.com" ipaddr="10.24.x.yyy"
> login="user" passwd="password" concurrent‑fencing="true"
> pcmk_action_limit="‑1" lanplus="true" action="off" delay="10" \
>         op monitor interval="20s" \
>         meta target‑role="Started"
> primitive redis ocf:heartbeat:redis \
>         params bin="/usr/local/bin/redis‑server"
> client_bin="/usr/local/bin/redis‑cli" port="6379"
> config="/etc/redis/redis.conf" socket_name="redis.sock"
> pidfile_name="redis.pid" \
>         meta target‑role="Started" is‑managed="true" \
>         op monitor interval="1s" role="Master" timeout="1s" on‑fail="fence"
> primitive res_vip ocf:heartbeat:IPaddr2 \
>         params ip="10.24.x.zzz" nic="bond0.xx" cidr_netmask="22" \
>         op monitor interval="10" \
>         meta target‑role="Started"
> ms redis_clone redis \
>         meta notify="true" is‑managed="true" ordered="false"
> interleave="true" globally‑unique="false" target‑role="Started"
> migration‑threshold="1"
> colocation redis‑first inf: redis_clone:Master res_vip
> order redis‑before‑vip inf: redis_clone:promote res_vip:start
> property $id="cib‑bootstrap‑options" \
>         dc‑version="1.1.10‑42f2063" \
>         cluster‑infrastructure="corosync" \
>         stonith‑enabled="true" \
>         no‑quorum‑policy="ignore" \
>         default‑resource‑stickiness="200" \
>         batch‑limit="300" \
>         migration‑limit="‑1"
> property $id="redis_replication" \
>         redis_REPL_INFO="example1.com"
> rsc_defaults $id="rsc‑options" \
>         migration‑threshold="1"
> 
> Thank you very much
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