StorageOS with AKS Kubernetes best practices

Dedicated instance groups

Cloud environments give users the ability to quickly scale the number of nodes in a cluster in response to their needs. Because of the ephemeral nature of the cloud, StorageOS recommends setting conservative downscaling policies.

For production clusters, it recommended to use dedicated instance groups for Stateful applications that allow the user to set different scaling policies and define StorageOS pools based on node selectors to collocate volumes.

Loosing a few nodes at the same time could cause the loss of data even when volume replicas are being used.

Use an external etcd cluster

StorageOS uses the etcd distributed key-value store to store essential cluster metadata and manage distributed configuration state. An embedded etcd instance is included in the StorageOS container, but for production environments, we recommend deploying using a external etcd cluster. For more details about and an example of how to run etcd, see the External Etcd Operations page.

It is highly recommended to use external etcd for cloud environments and place the etcd cluster on stable nodes. Placing the etcd on nodes that are recycled often might affect the normal operations of StorageOS.

StorageOS API username/password

The API grants full access to StorageOS functionality, therefore we recommend that the default administrative password of ‘storageos’ is reset to something unique and strong.

You can change the default parameters by encoding the apiUsername and apiPassword values (in base64) into the storageos-api secret.

To generate a unique password, a technique such as the following, which generates a pseudo-random 24 character string, may be used:

# Generate strong password
PASSWORD=$(cat -e /dev/urandom | tr -dc '[email protected]#$%^&*()_+~' | fold -w 24 | head -n 1)

# Convert password to base64 representation for embedding in a K8S secret
BASE64PASSWORD=$(echo -n $PASSWORD | base64)

Note that the Kubernetes secret containing a strong password must be created before bootstrapping the cluster. Multiple installation procedures use this Secret to create a StorageOS account when the cluster first starts.

Setup of storage on the hosts

We recommend creating a separate filesystem for StorageOS to mitigate risk of filling the root filesystem on nodes. This has to be done for each node in the cluster.

Follow the managing host storage best practices page for more details.

Resource reservations

StorageOS resource consumption depends on the workloads and the StorageOS features in use.

For production environments, it is recommended to test StorageOS using realistic workloads and tune resources accordingly.

The recommended minimum memory reservation for the StorageOS Pods is 235Mb. However it is recommended to prepare nodes so StorageOS can operate at least with 1-2GB of memory. StorageOS frees memory when possible.

StorageOS Pods resource allocation will impact directly on the availability of volumes in case of eviction or resource limit triggered restart. It is recommended to not limit StorageOS Pods.

StorageOS implements a storage engine, therefore limiting CPU consumption might affect the I/O throughput of your volumes.

Port blocking

StorageOS exposes ports to operate. It is recommended that the ports are not accessible from outside the scope of your cluster.