Anbox Cloud comes with support for High Availability (HA) for both Core and the Streaming Stack.
Next to Juju’s support for high availability of the Juju controller, you can add HA for the Anbox Management Service (AMS) and the Anbox Stream Gateway to ensure fault tolerance and higher uptime.
Enabling High Availability (HA for short) is achieved by adding new units via Juju.
This will allocate a new machine, run new instances of the scaled application and configure the cluster automatically.
Adding a unit is done with the following syntax:
juju add-unit <application name> -n <number of units to add>
For example, to go from 1 to 5 AMS units, you would run the following:
juju add-unit ams -n 4
By default, Juju allocates small machines to limit costs but you can request better resources by enforcing constraints:
juju set-constraints anbox-stream-gateway cores=4 memory=8GB
This is heavily recommended on production environments.
Anbox Cloud Core
Anbox Cloud Core HA requires additional AMS instances as well as a load balancer to spread out requests:
juju deploy ams-load-balancer
juju relate ams ams-load-balancer
juju add-unit ams -n 2
If you are using the amc snap on your machine, you can tell it to use the load balancer instead of talking directly to AMS:
amc remote add lb https://10.75.96.23:8444
amc remote set-default lb
The port to use is always 8444, the same AMS is listening on.
Anbox Streaming Stack
In the Streaming Stack, both the Agent and the Gateway can be run in HA. We recommend a minimum of 3 machines for the Streaming Stack.
juju add-unit anbox-stream-gateway -n 2
juju add-unit anbox-stream-agent -n 2
juju relate anbox-stream-gateway:api anbox-stream-gateway-lb:reverseproxy
This would give you 3 instances of both the Stream Gateway and the Stream Agent.
Checking status
When adding new units, Juju will create new machine so it may take a few minutes for
your cluster to be fully operational.
You can check juju status to see the current deployment status:
Model Controller Cloud/Region Version SLA Timestamp
default anbox-cloud localhost/localhost 2.8.0 unsupported 19:18:10Z
App Version Status Scale Charm Store Rev OS Notes
anbox-stream-agent active 3 anbox-stream-agent jujucharms 80 ubuntu
anbox-stream-gateway active 3 anbox-stream-gateway jujucharms 90 ubuntu
anbox-stream-gateway-lb active 1 haproxy jujucharms 56 ubuntu exposed
...
Unit Workload Agent Machine Public address Ports Message
anbox-stream-agent/0* active idle 0 10.212.218.11
anbox-stream-agent/1 active idle 6 10.212.218.178
anbox-stream-agent/2 active idle 5 10.212.218.193
anbox-stream-gateway-lb/0* active idle 2 10.212.218.104 80/tcp,443/tcp Unit is ready
anbox-stream-gateway/0* active idle 1 10.212.218.221 4000/tcp,7003/tcp
anbox-stream-gateway/1 active idle 3 10.212.218.105 4000/tcp,7004/tcp
anbox-stream-gateway/2 active idle 4 10.212.218.136 4000/tcp,7005/tcp
...
Notice the scale of each application indicating how much units an application has.
Scaling down
Scaling down can be done by removing units via Juju. You have to specifically target the unit that you want to remove:
juju remove-unit anbox-stream-agent/2
The cluster will reconfigure itself to work with the removed unit.