486b223e01
This replaces kube-master with kube_control_plane because of [1]:
The Kubernetes project is moving away from wording that is
considered offensive. A new working group WG Naming was created
to track this work, and the word "master" was declared as offensive.
A proposal was formalized for replacing the word "master" with
"control plane". This means it should be removed from source code,
documentation, and user-facing configuration from Kubernetes and
its sub-projects.
NOTE: The reason why this changes it to kube_control_plane not
kube-control-plane is for valid group names on ansible.
[1]: https://github.com/kubernetes/enhancements/blob/master/keps/sig-cluster-lifecycle/kubeadm/2067-rename-master-label-taint/README.md#motivation
54 lines
2.5 KiB
Markdown
54 lines
2.5 KiB
Markdown
Large deployments of K8s
|
|
========================
|
|
|
|
For a large scaled deployments, consider the following configuration changes:
|
|
|
|
* Tune [ansible settings](https://docs.ansible.com/ansible/intro_configuration.html)
|
|
for `forks` and `timeout` vars to fit large numbers of nodes being deployed.
|
|
|
|
* Override containers' `foo_image_repo` vars to point to intranet registry.
|
|
|
|
* Override the ``download_run_once: true`` and/or ``download_localhost: true``.
|
|
See download modes for details.
|
|
|
|
* Adjust the `retry_stagger` global var as appropriate. It should provide sane
|
|
load on a delegate (the first K8s master node) then retrying failed
|
|
push or download operations.
|
|
|
|
* Tune parameters for DNS related applications
|
|
Those are ``dns_replicas``, ``dns_cpu_limit``,
|
|
``dns_cpu_requests``, ``dns_memory_limit``, ``dns_memory_requests``.
|
|
Please note that limits must always be greater than or equal to requests.
|
|
|
|
* Tune CPU/memory limits and requests. Those are located in roles' defaults
|
|
and named like ``foo_memory_limit``, ``foo_memory_requests`` and
|
|
``foo_cpu_limit``, ``foo_cpu_requests``. Note that 'Mi' memory units for K8s
|
|
will be submitted as 'M', if applied for ``docker run``, and cpu K8s units
|
|
will end up with the 'm' skipped for docker as well. This is required as
|
|
docker does not understand k8s units well.
|
|
|
|
* Tune ``kubelet_status_update_frequency`` to increase reliability of kubelet.
|
|
``kube_controller_node_monitor_grace_period``,
|
|
``kube_controller_node_monitor_period``,
|
|
``kube_apiserver_pod_eviction_not_ready_timeout_seconds`` &
|
|
``kube_apiserver_pod_eviction_unreachable_timeout_seconds`` for better Kubernetes reliability.
|
|
Check out [Kubernetes Reliability](kubernetes-reliability.md)
|
|
|
|
* Tune network prefix sizes. Those are ``kube_network_node_prefix``,
|
|
``kube_service_addresses`` and ``kube_pods_subnet``.
|
|
|
|
* Add calico-rr nodes if you are deploying with Calico or Canal. Nodes recover
|
|
from host/network interruption much quicker with calico-rr. Note that
|
|
calico-rr role must be on a host without kube_control_plane or kube-node role (but
|
|
etcd role is okay).
|
|
|
|
* Check out the
|
|
[Inventory](getting-started.md#building-your-own-inventory)
|
|
section of the Getting started guide for tips on creating a large scale
|
|
Ansible inventory.
|
|
|
|
* Override the ``etcd_events_cluster_setup: true`` store events in a separate
|
|
dedicated etcd instance.
|
|
|
|
For example, when deploying 200 nodes, you may want to run ansible with
|
|
``--forks=50``, ``--timeout=600`` and define the ``retry_stagger: 60``.
|