Preparing the Cluster

This website/page will be End-of-life (EOL) after 31 August 2024. We recommend you to visit OpenEBS Documentation for the latest Mayastor documentation (v2.6 and above).

Mayastor is now also referred to as OpenEBS Replicated PV Mayastor.

Verify / Enable Huge Page Support

2MiB-sized Huge Pages must be supported and enabled on the mayastor storage nodes. A minimum number of 1024 such pages (i.e. 2GiB total) must be available exclusively to the Mayastor pod on each node, which should be verified thus:

grep HugePages /proc/meminfo

AnonHugePages:         0 kB
ShmemHugePages:        0 kB
HugePages_Total:    1024
HugePages_Free:      671
HugePages_Rsvd:        0
HugePages_Surp:        0

If fewer than 1024 pages are available then the page count should be reconfigured on the worker node as required, accounting for any other workloads which may be scheduled on the same node and which also require them. For example:

echo 1024 | sudo tee /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages

This change should also be made persistent across reboots by adding the required value to the file/etc/sysctl.conf like so:

echo vm.nr_hugepages = 1024 | sudo tee -a /etc/sysctl.conf

If you modify the Huge Page configuration of a node, you MUST either restart kubelet or reboot the node. Mayastor will not deploy correctly if the available Huge Page count as reported by the node's kubelet instance does not satisfy the minimum requirements.

Label Mayastor Node Candidates

All worker nodes which will have Mayastor pods running on them must be labelled with the OpenEBS engine type "mayastor". This label will be used as a node selector by the Mayastor Daemonset, which is deployed as a part of the Mayastor data plane components installation. To add this label to a node, execute:

kubectl label node <node_name> openebs.io/engine=mayastor

If you set csi.node.topology.nodeSelector: true, then you will need to label the worker nodes accordingly to csi.node.topology.segments. Both csi-node and agent-ha-node Daemonsets will include the topology segments into the node selector.