Replacing a Controller Node¶
Replace Failed Node¶
First, create a YAML file defining node index to remove. Node index reflects suffix of instance name in nova list output. In this following text overcloud-controller-1 node is replaced with overcloud-controller-3:
$ cat ~/remove.yaml
parameter_defaults:
ControllerRemovalPolicies:
[{'resource_list': ['1']}]
Then, re-deploy overcloud including the extra environment file:
openstack overcloud deploy --templates --control-scale 3 -e ~/remove.yaml
The old node will be removed and a new one will be added. Because some puppet modules don’t support nodes replacement, re-deployment fails and a couple of manual changes are needed to fix controller nodes setup. Connect to one of remaining controller nodes and delete the failed node from Pacemaker/Corosync cluster:
crm_node -R overcloud-controller-1 --force
Delete the failed node from RabbitMQ cluster:
rabbitmqctl forget_cluster_node rabbit@overcloud-controller-1
Delete the failed node from MongoDB:
# connect to MongoDB on any of remaining nodes:
mongo --host <node ip>
# check status of MongoDB cluster:
rs.status()
# remove the failed node:
rs.remove('<node_ip>:27017')
Update list of nodes in Galera cluster:
pcs resource update galera wsrep_cluster_address=gcomm://overcloud-controller-0,overcloud-controller-3,overcloud-controller-2
Start Pacemaker/Corosync on the new node:
pcs cluster node add overcloud-controller-3
pcs cluster start overcloud-controller-3
Enable keystone service on the new node:
copy /etc/keystone from a remaining node to the new node
set admin_bind_host and public_bind_host in /etc/keystone/keystone.conf to node's IP
pcs resource cleanup openstack-keystone-clone overcloud-controller-3
Re-deploy overcloud again:
openstack overcloud deploy --templates --control-scale 3
Note
If deployment fails with error Failed to call refresh: Could not restart Service[httpd] then try re-deploy again.
Completing Update¶
Delete the failed node from /etc/corosync/corosync.conf file and restart Corosync one by one on each node:
systemctl restart corosync
When re-deployment finishes, connect to one of controller nodes and start services on the new node:
pcs resource cleanup neutron-server-clone
pcs resource cleanup openstack-nova-api-clone
pcs resource cleanup openstack-nova-consoleauth-clone
pcs resource cleanup openstack-heat-engine-clone
pcs resource cleanup openstack-cinder-api-clone
pcs resource cleanup openstack-glance-registry-clone
pcs resource cleanup httpd-clone
Replacing Bootstrap Node¶
If node with index 0 is being replaced it’s necessary to edit heat templates and change bootstrap node index before starting replacement. Open overcloud.yaml file in root directory of heat templates and change lines:
bootstrap_nodeid: {get_attr: [Controller, resource.0.hostname]}
bootstrap_nodeid_ip: {get_attr: [Controller, resource.0.ip_address]}
to:
bootstrap_nodeid: {get_attr: [Controller, resource.1.hostname]}
bootstrap_nodeid_ip: {get_attr: [Controller, resource.1.ip_address]}