How to deploy MongoDB K8s
This is a guide on how to deploy Charmed MongoDB K8s as a replica set or a sharded cluster.
Summary
Create a MongoDB replica set
You can create one or multiple replicas at once when deploying MongoDB K8s.
Deploy a single replica
To deploy a single unit of MongoDB as a replica set, run:
juju deploy mongodb-k8s --trust
The
--trustflag is necessary to grant the application access to the Kubernetes cluster.
Deploy multiple replicas
To deploy MongoDB with multiple replicas, specify the number of desired replicas with the -n option:
juju deploy mongodb-k8s -n <number_of_replicas>
Create a MongoDB sharded cluster
To create a sharded cluster, we must first deploy each cluster component separately with a manually defined role, then integrate them.
Deploy cluster components with a single replica
Deploying a shard application will assign it one replica by default.
To deploy a sharded cluster with two shards, run:
juju deploy mongodb-k8s --config role="config-server" <config_server_name>
juju deploy mongodb-k8s --config role="shard" <shard_name_0>
juju deploy mongodb-k8s --config role="shard" <shard_name_1>
This will deploy the latest stable release . To specify a different version, use the
--channelflag, e.g.--channel=6/beta.
Deploy cluster components with multiple replicas
To configure the amount of replicas for a shard or config-server during deployment, just use the -n flag.
To deploy a shard and config-server with 3 replicas each, run:
juju deploy mongodb-k8s --config role="shard" <shard_name> -n 3
juju deploy mongodb-k8s --config role="config-server" <config_server_name> -n 3
This will deploy the latest stable release . To specify a different version, use the
--channelflag, e.g.--channel=6/beta.
Note that you can also change the number of replicas for a shard or config server after deployment. See Scale replicas and shards > How to add shards to a cluster.
Integrate cluster components
To create a cluster, integrate the shard applications with the config-server application.
For the case of two shards and one config server, you would run:
juju integrate config-server:config-server <shard_name_0>:sharding
juju integrate config-server:config-server <shard_name_1>:sharding