openstack-ansible/doc/source/install-guide/ops-galera-recoverycontainer.rst
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Change-Id: I3eedadc8ba441b4d931720dd6e3f7f3489302a9c
Co-Authored-By: Matt Kassawara <mkassawara@gmail.com>
2015-06-11 09:17:56 -05:00

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`Home <index.html>`__ OpenStack Ansible Installation Guide
Rebuilding a container
----------------------
Sometimes recovering from a failure requires rebuilding one or more
containers.
#. Disable the failed node on the load balancer.
Do not rely on the load balancer health checks to disable the node.
If the node is not disabled, the load balancer will send SQL requests
to it before it rejoins the cluster and cause data inconsistencies.
#. Use the following commands to destroy the container and remove
MariaDB data stored outside of the container. In this example, node 3
failed.
.. code-block:: bash
$ lxc-stop -n node3_galera_container-3ea2cbd3
$ lxc-destroy -n node3_galera_container-3ea2cbd3
$ rm -rf /openstack/node3_galera_container-3ea2cbd3/*
#. Run the host setup playbook to rebuild the container specifically on
node 3:
.. code-block:: bash
$ openstack-ansible setup-hosts.yml -l node3 \
-l node3_galera_container-3ea2cbd3
The playbook will also restart all other containers on the node.
#. Run the infrastructure playbook to configure the container
specifically on node 3:
.. code-block:: bash
$ openstack-ansible infrastructure-setup.yml \
-l node3_galera_container-3ea2cbd3
The new container runs a single-node Galera cluster, a dangerous
state because the environment contains more than one active database
with potentially different data.
.. code-block:: bash
$ ansible galera_container -m shell -a "mysql \
-h localhost -e 'show status like \"%wsrep_cluster_%\";'"
node3_galera_container-3ea2cbd3 | success | rc=0 >>
Variable_name Value
wsrep_cluster_conf_id 1
wsrep_cluster_size 1
wsrep_cluster_state_uuid da078d01-29e5-11e4-a051-03d896dbdb2d
wsrep_cluster_status Primary
node2_galera_container-49a47d25 | success | rc=0 >>
Variable_name Value
wsrep_cluster_conf_id 4
wsrep_cluster_size 2
wsrep_cluster_state_uuid 338b06b0-2948-11e4-9d06-bef42f6c52f1
wsrep_cluster_status Primary
node4_galera_container-76275635 | success | rc=0 >>
Variable_name Value
wsrep_cluster_conf_id 4
wsrep_cluster_size 2
wsrep_cluster_state_uuid 338b06b0-2948-11e4-9d06-bef42f6c52f1
wsrep_cluster_status Primary
#. Restart MariaDB in the new container and verify that it rejoins the
cluster.
.. code-block:: bash
$ ansible galera_container -m shell -a "mysql \
-h localhost -e 'show status like \"%wsrep_cluster_%\";'"
node2_galera_container-49a47d25 | success | rc=0 >>
Variable_name Value
wsrep_cluster_conf_id 5
wsrep_cluster_size 3
wsrep_cluster_state_uuid 338b06b0-2948-11e4-9d06-bef42f6c52f1
wsrep_cluster_status Primary
node3_galera_container-3ea2cbd3 | success | rc=0 >>
Variable_name Value
wsrep_cluster_conf_id 5
wsrep_cluster_size 3
wsrep_cluster_state_uuid 338b06b0-2948-11e4-9d06-bef42f6c52f1
wsrep_cluster_status Primary
node4_galera_container-76275635 | success | rc=0 >>
Variable_name Value
wsrep_cluster_conf_id 5
wsrep_cluster_size 3
wsrep_cluster_state_uuid 338b06b0-2948-11e4-9d06-bef42f6c52f1
wsrep_cluster_status Primary
#. Enable the failed node on the load balancer.
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.. include:: navigation.txt