Percona XtraDB Cluster provides an active/active MySQL compatible alternative implemented using the Galera synchronous replication extensions.
Percona XtraDB Cluster is a high availability and high scalability solution for
MySQL clustering. Percona XtraDB Cluster integrates Percona Server with the
Galera library of MySQL high availability solutions in a single product package
which enables you to create a cost-effective MySQL cluster.
This charm deploys Percona XtraDB Cluster onto Ubuntu.
WARNING: Its critical that you follow the bootstrap process detailed in this
document in order to end up with a running Active/Active Percona Cluster.
If you are deploying this charm on MAAS or in an environment without direct
access to the internet, you will need to allow access to repo.percona.com
as the charm installs packages direct from the Percona respositories. If you
are using squid-deb-proxy, follow the steps below:
echo "repo.percona.com" | sudo tee /etc/squid-deb-proxy/mirror-dstdomain.acl.d/40-percona sudo service squid-deb-proxy restart
The first service unit deployed acts as the seed node for the rest of the
cluster; in order for the cluster to function correctly, the same MySQL passwords
must be used across all nodes:
cat > percona.yaml << EOF percona-cluster: root-password: my-root-password sst-password: my-sst-password EOF
Once you have created this file, you can deploy the first seed unit:
juju deploy --config percona.yaml percona-cluster
Once this node is full operational, you can add extra units one at a time to the
juju add-unit percona-cluster
A minimium cluster size of three units is recommended.
There are two mutually exclusive high availability options: using virtual
IP(s) or DNS. In both cases, a relationship to hacluster is required which
provides the corosync back end HA functionality.
To use virtual IP(s) the clustered nodes must be on the same subnet such that
the VIP is a valid IP on the subnet for one of the node's interfaces and each
node has an interface in said subnet. The VIP becomes a highly-available API
At a minimum, the config option 'vip' must be set in order to use virtual IP
HA. If multiple networks are being used, a VIP should be provided for each
network, separated by spaces. Optionally, vip_iface or vip_cidr may be
To use DNS high availability there are several prerequisites. However, DNS HA
does not require the clustered nodes to be on the same subnet.
Currently the DNS HA feature is only available for MAAS 2.0 or greater
environments. MAAS 2.0 requires Juju 2.0 or greater. The clustered nodes must
have static or "reserved" IP addresses registered in MAAS. The DNS hostname(s)
must be pre-registered in MAAS before use with DNS HA.
At a minimum, the config option 'dns-ha' must be set to true and
'os-access-hostname' must be set in order to use DNS HA.
The charm will throw an exception in the following circumstances:
If neither 'vip' nor 'dns-ha' is set and the charm is related to hacluster
If both 'vip' and 'dns-ha' are set as they are mutually exclusive
If 'dns-ha' is set and os-access-hostname is not set
Network Space support
This charm supports the use of Juju Network Spaces, allowing the charm to be bound to network space configurations managed directly by Juju. This is only supported with Juju 2.0 and above.
You can ensure that database connections are bound to a specific network space by binding the appropriate interfaces:
juju deploy percona-cluster --bind "shared-db=internal-space"
alternatively these can also be provided as part of a juju native bundle configuration:
percona-cluster: charm: cs:xenial/percona-cluster num_units: 1 bindings: shared-db: internal-space
NOTE: Spaces must be configured in the underlying provider prior to attempting to use them.
NOTE: Existing deployments using the access-network configuration option will continue to function; this option is preferred over any network space binding provided if set.
Note that Percona XtraDB Cluster is not a 'scale-out' MySQL solution; reads
and writes are channelled through a single service unit and synchronously
replicated to other nodes in the cluster; reads/writes are as slow as the
slowest node you have in your deployment.
Network interface on which to place the Virtual IP.
Location on the filesystem where binlogs are going to be placed. Default mimics what mysql-common package would do for mysql. Make sure you do not put binlogs inside mysql datadir (/var/lib/mysql/)!
Sets the max_binlog_size mysql configuration option, which will limit the size of the binary log files. The server will automatically rotate binlgos after they grow to be bigger than this value. Keep in mind that transactions are never split between binary logs, so therefore binary logs might get larger than configured value.
The IP address and netmask of the 'access' network (e.g. 192.168.0.0/24) . This network will be used for access to database services.
Virtual IP to use to front Percona XtraDB Cluster in active/active HA configuration
The IP address and netmask of the cluster (replication) network (e.g. 192.168.0.0/24) . This network will be used for wsrep_cluster replication.
Package install location for Percona XtraDB Cluster (defaults to distro for >= 14.04)
Default multicast port number that will be used to communicate between HA Cluster nodes.
Default network interface on which HA cluster will bind to communication with the other members of the HA Cluster.
Sets the expire_logs_days mysql configuration option, which will make mysql server automatically remove logs older than configured number of days.
Turns on MySQL binary logs. The placement of the logs is controlled with the binlogs_path config option.
Root password for MySQL access; must be configured pre-deployment for Active-Active clusters.
A comma-separated list of nagios servicegroups. If left empty, the nagios_context will be used as the servicegroup.
Sets table_open_cache (formerly known as table_cache) to mysql.
Turns on innodb_file_per_table option, which will make MySQL put each InnoDB table into separate .idb file. Existing InnoDB tables will remain in ibdata1 file - full dump/import is needed to get rid of large ibdata1 file
Re-sync account password for new cluster nodes; must be configured pre-deployment for Active-Active clusters.
Adds two config options (wsrep_drupal_282555_workaround and wsrep_retry_autocommit) as a workaround for Percona Primary Key bug (see LP 1366997).
Key ID to import to the apt keyring to support use with arbitary source configuration from outside of Launchpad archives or PPA's.
By default this value will be set according to 50% of system total memory but also can be set to any specific value for the system. Supported suffixes include K/M/G/T. If suffixed with %, one will get that percentage of system total memory allocated.
Maximum connections to allow. A value of -1 means use the server's compiled-in default. This is not typically that useful so the charm will configure PXC with a default max-connections value of 600.
Use DNS HA with MAAS 2.0. Note if this is set do not set vip settings below.
(DEPRECATED - use innodb-buffer-pool-size) How much data should be kept in memory in the DB. This will be used to tune settings in the database server appropriately. Supported suffixes include K/M/G/T. If suffixed with %, one will get that percentage of RAM allocated to the dataset.
Netmask that will be used for the Virtual IP.
Used by the nrpe-external-master subordinate charm. A string that will be prepended to instance name to set the host name in nagios. So for instance the hostname would be something like: . juju-myservice-0 . If you're running multiple environments with the same services in them this allows you to differentiate between them.
The number of seconds the server waits for activity on a noninteractive connection before closing it. -1 means use the server's compiled in default.
The hostname or address of the access endpoint for percona-cluster.
Apply system hardening. Supports a space-delimited list of modules to run. Supported modules currently include os, ssh, apache and mysql.
Percona method for taking the State Snapshot Transfer (SST), can be: 'rsync', 'xtrabackup', 'xtrabackup-v2', 'mysqldump', 'skip' - see https://www.percona.com/doc/percona-xtradb-cluster/5.5/wsrep-system-index.html#wsrep_sst_method
Minimum number of units expected to exist before charm will attempt to bootstrap percona cluster. If no value is provided this setting is ignored.
If True enables IPv6 support. The charm will expect network interfaces to be configured with an IPv6 address. If set to False (default) IPv4 is expected. . NOTE: these charms do not currently support IPv6 privacy extension. In order for this charm to function correctly, the privacy extension must be disabled and a non-temporary address must be configured/available on your network interface.