[ClusterLabs] Cloned IP not moving back after node restart or standby

[Ken Gaillot]

On 06/02/2017 06:33 AM, Takehiro Matsushima wrote:
> Hi,
> 
> You should not clone IPaddr2 resource.
> Clone means that to run the resource at same time on both nodes, so
> these nodes will have same duplicated IP address on a network.
> 
> Specifically, you need to configure a IPaddr2 resource runs on a node
> which cloned nginx is running, by collocation constraint.
> 
> However please note that does not work as a load-balancer.
> 
> Regards,
> Takehiro

Actually, IPaddr2 provides special logic for being run as a unique clone
(unique meaning that multiple instances of the clone can run on one
node). It uses the iptables "clusterip" feature to utilize multicast
Ethernet addresses (something different from multicast IP) so that each
node handles only certain requests to the IP.

> 2017/05/31 午前1:48 "Przemyslaw Kulczycki" <upr at avaleo.net
> <mailto:upr at avaleo.net>>:
> 
>     Hi.
>     I'm trying to setup a 2-node corosync+pacemaker cluster to function
>     as an active-active setup for nginx with a shared IP.
> 
>     I've discovered (much to my disappointment) that every time I
>     restart one node or put it in standby, the second instance of the
>     cloned IP gets moved to the first node and doesn't go back once the
>     second node is available, even though I have set stickiness to 0.

>     [upr at webdemo3 ~]$ sudo pcs status
>     Cluster name: webdemo_cluster2
>     Stack: corosync
>     Current DC: webdemo3 (version 1.1.15-11.el7_3.4-e174ec8) - partition
>     with quorum
>     Last updated: Tue May 30 18:40:18 2017          Last change: Tue May
>     30 17:56:24 2017 by hacluster via crmd on webdemo4
> 
>     2 nodes and 4 resources configured
> 
>     Online: [ webdemo3 webdemo4 ]
> 
>     Full list of resources:
> 
>      Clone Set: ha-ip-clone [ha-ip] (unique)
>          ha-ip:0    (ocf::heartbeat:IPaddr2):       Started webdemo3
>          ha-ip:1    (ocf::heartbeat:IPaddr2):       Started webdemo3
>      Clone Set: ha-nginx-clone [ha-nginx] (unique)
>          ha-nginx:0 (ocf::heartbeat:nginx): Started webdemo3
>          ha-nginx:1 (ocf::heartbeat:nginx): Started webdemo4
> 
>     Failed Actions:
>     * ha-nginx:0_monitor_20000 on webdemo3 'not running' (7): call=108,
>     status=complete, exitreason='none',
>         last-rc-change='Tue May 30 17:56:46 2017', queued=0ms, exec=0ms
> 
> 
>     Daemon Status:
>       corosync: active/enabled
>       pacemaker: active/enabled
>       pcsd: active/enabled
> 
>     [upr at webdemo3 ~]$ sudo pcs config --full
>     Cluster Name: webdemo_cluster2
>     Corosync Nodes:
>      webdemo3 webdemo4
>     Pacemaker Nodes:
>      webdemo3 webdemo4
> 
>     Resources:
>      Clone: ha-ip-clone
>       Meta Attrs: clone-max=2 clone-node-max=2 globally-unique=true
>     *stickiness=0*
>
>       Resource: ha-ip (class=ocf provider=heartbeat type=IPaddr2)
>        Attributes: ip=10.75.39.235 cidr_netmask=24 clusterip_hash=sourceip
>        Operations: start interval=0s timeout=20s (ha-ip-start-interval-0s)
>                    stop interval=0s timeout=20s (ha-ip-stop-interval-0s)
>                    monitor interval=10s timeout=20s
>     (ha-ip-monitor-interval-10s)
>      Clone: ha-nginx-clone
>       Meta Attrs: globally-unique=true clone-node-max=1
>       Resource: ha-nginx (class=ocf provider=heartbeat type=nginx)
>        Operations: start interval=0s timeout=60s
>     (ha-nginx-start-interval-0s)
>                    stop interval=0s timeout=60s (ha-nginx-stop-interval-0s)
>                    monitor interval=20s timeout=30s
>     (ha-nginx-monitor-interval-20s)
> 
>     Stonith Devices:
>     Fencing Levels:
> 
>     Location Constraints:
>     Ordering Constraints:
>     Colocation Constraints:
>       ha-ip-clone with ha-nginx-clone (score:INFINITY)
>     (id:colocation-ha-ip-ha-nginx-INFINITY)
>     Ticket Constraints:
> 
>     Alerts:
>      No alerts defined
> 
>     Resources Defaults:
>      resource-stickiness: 100
>     Operations Defaults:
>      No defaults set
> 
>     Cluster Properties:
>      cluster-infrastructure: corosync
>      cluster-name: webdemo_cluster2
>      dc-version: 1.1.15-11.el7_3.4-e174ec8
>      have-watchdog: false
>      last-lrm-refresh: 1496159785
>      no-quorum-policy: ignore
>      stonith-enabled: false
> 
>     Quorum:
>       Options:
> 
>     Am I doing something incorrectly?
> 
>     Additionally, I'd like to know what's the difference between these
>     commands:
> 
>     sudo pcs resource update ha-ip-clone stickiness=0
> 
>     sudo pcs resource meta ha-ip-clone resource-stickiness=0
> 
> 
>     They seem to set the same thing, but there might be a subtle difference.
> 
>     -- 
>     Best Regards
>      
>     Przemysław Kulczycki
>     System administrator
>     Avaleo
> 
>     Email: upr at avaleo.net <mailto:upr at avaleo.net>