Calculate a maintenance window duration

This section provides the background information on the approximate time spent on operations for pods of different purposes, possible data plane impact during these operations, and the possibility of a parallel pods update. Such data helps the cloud administrators to correctly estimate maintenance windows and impacts on the workloads for your OpenStack deployment.

Note

The approximate time cost to upgrade an OpenStack cloud with 50 compute nodes is 2 hours.

Note

During the MOS managed cluster update, numerous StackLight alerts may fire. This is an expected behavior. Ignore or temporarily mute them as described in Mirantis Container Cloud Operations Guide: Silence alerts.

Maintenance window calculation

Pod name

Pod description

Kubernetes kind

Readiness time

Data plane impact

Parallel update

[*]-api

Contains API services of OpenStack components. Horizontally well scalable.

Deployment

<30s

NO

YES (batches 10% of overall count)

[*]-conductor

Contains proxy service between OpenStack and database.

Deployment

<30s

NO

YES (batches 10% of overall count)

[*]-scheduler

Spreads OpenStack resources between nodes.

Deployment

<30s

NO

YES (batches 10% of overall count)

[*]-worker
[*]-engine
[*]-volume
[*]-backup
[*]

Process user requests.

Deployment

<30s

NO

YES (batches 10% of overall count)

nova-compute

Processes user requests, interacts with the data plane services.

DaemonSet

<120s

NO

YES (batches 10% of overall count)

neutron-l3-agent

Creates virtual routers (spawns keepalived processes for the HA routers).

DaemonSet

10-15m (for 100 routers)

YES

NO (one by one)

neutron-openvswitch-agent

Configures tunnels between nodes.

DaemonSet

<120s

NO

YES (batches 10% of overall count)

neutron-dhcp-agent

Configures the DHCP server for the networking service.

DaemonSet

<30s

Partially (only if the downtime exceeds the lease timeout.

YES (batches 10% of overall count)

neutron-metadata-agent

Provides metadata information to user workloads (VMs).

DaemonSet

<30s

NO

YES (batches 10% of overall count)

libvirt

Starts the libvirtd communication daemon.

DaemonSet

<30s

NO

YES (batches 10% of overall count)

openvswitch-[*]

Sets up the Open vSwitch datapaths and then operates the switching across each bridge.

DaemonSet

<30s

YES

NO (one by one)

mariadb-[*]

Contains persistent storage (database) for OpenStack deployment.

StatefulSet

<180s

NO

NO (one by one)

memcached-[*]

Contains the memory object caching system.

Deployment

<30s

NO

NO (one by one)

[*]-rabbitmq-[*]

Contains the messaging service for OpenStack.

StatefulSet

<30s

NO

NO (one by one)