Cluster high memory pressure
Symptom
A CustomerClusterHighMemoryPressure alert is firing. It indicates a filesystem on a node in your cluster is almost full.
CustomerClusterHighMemoryPressure alerts are sent to subscribers via email.
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Cluster nodes can suffer from memory pressure (less than 5% memory available and a high rate of major page faults used by the alerts), but the cluster may have lots of unused memory. The pod distribution across the cluster node may be uneven with one node getting the memory hungry pods while other nodes are lightly loaded.
Observations
Solutions
This section provides solutions that should help resolve the issue in most cases.
Increase cluster node instance type
The memory available to a cluster node is determined by the instance type. Cluster nodes are usually t3a-xlarge EC2 instances
with 16GB memory. The next larger instance type, t3a.2xlarge, has 32GB memory. There are no instance types larger than t3a.2xlarge.
Increasing the instance type means you will have to pay for the larger instances.
| All nodes in the cluster should be upgraded if the instance type is increased! |
The instance type of the cluster nodes can be changed in AWS. Magnolia deployments will be unavailable while the node instance type is upgraded.
Add a node to the cluster
We recommend that each Magnolia instance and its database be run on a separate node in the cluster: the author plus two public instances can each be run on separate nodes and each Magnolia instance can have enough memory (10 - 12 GB for author instances and 8 - 10 GB for public instances).
If you want to run more than three Magnolia instances on the cluster, additional nodes can be added to the cluster.
You have to pay more to increase the number of nodes.
Adding a node to cluster won’t necessarily redistribute the workloads more evenly across the cluster.
You may need to redeploy Magnolia after adding a cluster node.