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To: pgsql-admin@postgresql.org
Subject: Pacemaker dynamic membership
Date: Wed, 7 Oct 2015 10:44:10 +0300
Message-ID: <5614CD4A.7020900@postgrespro.ru> (raw )
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Hello.
We was looking the ways to utilize Corosync/Pacemaker stack for creating a
high-availability cluster of PostgreSQL servers with automatic failover.
We are using Corosync (2.3.4) as a messaging layer and a stateful
master/slave
Resource Agent (pgsql) with Pacemaker (1.1.12) on CentOS 7.1.
Things work pretty well for a static cluster - where membership is
defined up front.
However, we needed to be able to seamlessly add new machines (node) to
the cluster and remove
existing ones from it, without service interruption. And we ran into a
problem.
Is it possible to add a new node dynamically without interruption?
Here are the steps we are using to add a node:
# pcs property show
Cluster Properties:
cluster-infrastructure: corosync
cluster-name: mycluster1
dc-version: 1.1.13-a14efad
have-watchdog: false
last-lrm-refresh: 1444042099
no-quorum-policy: stop
stonith-action: reboot
stonith-enabled: true
Node Attributes:
pi01: pgsql-data-status=STREAMING|SYNC
pi02: pgsql-data-status=STREAMING|POTENTIAL
pi03: pgsql-data-status=LATEST
# pcs resource show --full
Group: master-group
Resource: vip-master (class=ocf provider=heartbeat type=IPaddr2)
Attributes: ip=192.168.242.100 nic=eth0 cidr_netmask=24
Operations: start interval=0s timeout=60s on-fail=restart
(vip-master-start-interval-0s)
monitor interval=10s timeout=60s on-fail=restart
(vip-master-monitor-interval-10s)
stop interval=0s timeout=60s on-fail=block
(vip-master-stop-interval-0s)
Resource: vip-rep (class=ocf provider=heartbeat type=IPaddr2)
Attributes: ip=192.168.242.101 nic=eth0 cidr_netmask=24
Meta Attrs: migration-threshold=0
Operations: start interval=0s timeout=60s on-fail=stop
(vip-rep-start-interval-0s)
monitor interval=10s timeout=60s on-fail=restart
(vip-rep-monitor-interval-10s)
stop interval=0s timeout=60s on-fail=ignore
(vip-rep-stop-interval-0s)
Master: msPostgresql
Meta Attrs: master-max=1 master-node-max=1 clone-max=3
clone-node-max=1 notify=true
Resource: pgsql (class=ocf provider=heartbeat type=pgsql)
Attributes: pgctl=/usr/pgsql-9.5/bin/pg_ctl
psql=/usr/pgsql-9.5/bin/psql pgdata=/var/lib/pgsql/9.5/data/
rep_mode=sync node_list="pi01 pi02 pi03" restore_command="cp
/var/lib/pgsql/9.5/data/wal_archive/%f %p"
primary_conninfo_opt="user=repl password=super-pass-for-repl
keepalives_idle=60 keepalives_interval=5 keepalives_count=5"
master_ip=192.168.242.100 restart_on_promote=true check_wal_receiver=true
Operations: start interval=0s timeout=60s on-fail=restart
(pgsql-start-interval-0s)
monitor interval=4s timeout=60s on-fail=restart
(pgsql-monitor-interval-4s)
monitor role=Master timeout=60s on-fail=restart
interval=3s (pgsql-monitor-interval-3s-role-Master)
promote interval=0s timeout=60s on-fail=restart
(pgsql-promote-interval-0s)
demote interval=0s timeout=60s on-fail=stop
(pgsql-demote-interval-0s)
stop interval=0s timeout=60s on-fail=block
(pgsql-stop-interval-0s)
notify interval=0s timeout=60s (pgsql-notify-interval-0s)
# pcs cluster auth pi01 pi02 pi03 pi05 -u hacluster -p hacluster
pi01: Authorized
pi02: Authorized
pi03: Authorized
pi05: Authorized
# pcs cluster node add pi05 --start
pi01: Corosync updated
pi02: Corosync updated
pi03: Corosync updated
pi05: Succeeded
pi05: Starting Cluster...
# crm_mon -Afr1
Last updated: Fri Oct 2 16:59:54 2015 Last change: Fri Oct 2
16:59:23 2015 by hacluster via crmd on pi02
Stack: corosync
Current DC: pi02 (version 1.1.13-a14efad) - partition with quorum
4 nodes and 8 resources configured
Online: [ pi01 pi02 pi03 pi05 ]
Full list of resources:
Resource Group: master-group
vip-master (ocf::heartbeat:IPaddr2): Started pi02
vip-rep (ocf::heartbeat:IPaddr2): Started pi02
Master/Slave Set: msPostgresql [pgsql]
Masters: [ pi02 ]
Slaves: [ pi01 pi03 ]
fence-pi01 (stonith:fence_ssh): Started pi02
fence-pi02 (stonith:fence_ssh): Started pi01
fence-pi03 (stonith:fence_ssh): Started pi01
Node Attributes:
* Node pi01:
+ master-pgsql : 100
+ pgsql-data-status : STREAMING|SYNC
+ pgsql-receiver-status : normal
+ pgsql-status : HS:sync
* Node pi02:
+ master-pgsql : 1000
+ pgsql-data-status : LATEST
+ pgsql-master-baseline : 0000000008000098
+ pgsql-receiver-status : ERROR
+ pgsql-status : PRI
* Node pi03:
+ master-pgsql : -INFINITY
+ pgsql-data-status : STREAMING|POTENTIAL
+ pgsql-receiver-status : normal
+ pgsql-status : HS:potential
* Node pi05:
Migration Summary:
* Node pi01:
* Node pi03:
* Node pi02:
* Node pi05:
# pcs resource update msPostgresql pgsql master-max=1 master-node-max=1
clone-max=4 clone-node-max=1 notify=true
# crm_mon -Afr1
Last updated: Fri Oct 2 17:04:36 2015 Last change: Fri Oct 2
17:04:07 2015 by root via
cibadmin on pi01
Stack: corosync
Current DC: pi02 (version 1.1.13-a14efad) - partition with quorum
4 nodes and 9 resources configured
Online: [ pi01 pi02 pi03 pi05 ]
Full list of resources:
Resource Group: master-group
vip-master (ocf::heartbeat:IPaddr2): Started pi02
vip-rep (ocf::heartbeat:IPaddr2): Started pi02
Master/Slave Set: msPostgresql [pgsql]
Masters: [ pi02 ]
Slaves: [ pi01 pi03 ]
Stopped: [ pi05 ]
fence-pi01 (stonith:fence_ssh): Started pi02
fence-pi02 (stonith:fence_ssh): Started pi01
fence-pi03 (stonith:fence_ssh): Started pi01
Node Attributes:
* Node pi01:
+ master-pgsql : 100
+ pgsql-data-status : STREAMING|SYNC
+ pgsql-receiver-status : normal
+ pgsql-status : HS:sync
* Node pi02:
+ master-pgsql : 1000
+ pgsql-data-status : LATEST
+ pgsql-master-baseline : 0000000008000098
+ pgsql-receiver-status : ERROR
+ pgsql-status : PRI
* Node pi03:
+ master-pgsql : -INFINITY
+ pgsql-data-status : STREAMING|POTENTIAL
+ pgsql-receiver-status : normal
+ pgsql-status : HS:potential
* Node pi05:
+ master-pgsql : -INFINITY
+ pgsql-status : STOP
Migration Summary:
* Node pi01:
* Node pi03:
* Node pi02:
* Node pi05:
pgsql: migration-threshold=1 fail-count=1000000 last-failure='Fri
Oct 2 17:04:13 2015'
Failed Actions:
* pgsql_start_0 on pi05 'unknown error' (1): call=27, status=complete,
exitreason='My data may be
inconsistent. You have to remove /var/lib/pgsql/tmp/PGSQL.lock file to
force start.',
last-rc-change='Fri Oct 2 17:04:10 2015', queued=0ms, exec=2553ms
# pcs resource update pgsql pgsql node_list="pi01 pi02 pi03 pi05"
And here we fall into the trouble pgsql-status is now STOP!!!!!!!!
# crm_mon -Afr1
Last updated: Fri Oct 2 17:07:05 2015 Last change: Fri Oct 2
17:06:37 2015
by root via cibadmin on pi01
Stack: corosync
Current DC: pi02 (version 1.1.13-a14efad) - partition with quorum
4 nodes and 9 resources configured
Online: [ pi01 pi02 pi03 pi05 ]
Full list of resources:
Resource Group: master-group
vip-master (ocf::heartbeat:IPaddr2): Stopped
vip-rep (ocf::heartbeat:IPaddr2): Stopped
Master/Slave Set: msPostgresql [pgsql]
Slaves: [ pi02 ]
Stopped: [ pi01 pi03 pi05 ]
fence-pi01 (stonith:fence_ssh): Started pi02
fence-pi02 (stonith:fence_ssh): Started pi01
fence-pi03 (stonith:fence_ssh): Started pi01
Node Attributes:
* Node pi01:
+ master-pgsql : -INFINITY
+ pgsql-data-status : STREAMING|SYNC
+ pgsql-status : STOP
* Node pi02:
+ master-pgsql : -INFINITY
+ pgsql-data-status : LATEST
+ pgsql-status : STOP
* Node pi03:
+ master-pgsql : -INFINITY
+ pgsql-data-status : STREAMING|POTENTIAL
+ pgsql-status : STOP
* Node pi05:
+ master-pgsql : -INFINITY
+ pgsql-status : STOP
Migration Summary:
* Node pi01:
* Node pi03:
* Node pi02:
* Node pi05:
Do you know the way to add new node to cluster without this disruption?
Maybe some command or something else?
--
Nikolay Popov
n.popov@postgrespro.ru
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
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Subject: Re: Pacemaker dynamic membership
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