2d18e19263
* Add dns_replicas, dns_memory/cpu_limit/requests vars for dns related apps. * When kube_log_level=4, log dnsmasq queries as well. * Add log level control for skydns (part of kubedns app). * Add limits/requests vars for dnsmasq (part of kubedns app) and dnsmasq daemon set. * Drop string defaults for kube_log_level as it is int and is defined in the global vars as well. * Add docs Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
31 lines
1.5 KiB
Markdown
31 lines
1.5 KiB
Markdown
Large deployments of K8s
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For a large scaled deployments, consider the following configuration changes:
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* Tune [ansible settings](http://docs.ansible.com/ansible/intro_configuration.html)
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for `forks` and `timeout` vars to fit large numbers of nodes being deployed.
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* Override containers' `foo_image_repo` vars to point to intranet registry.
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* Override the ``download_run_once: true`` to download container images only once
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then push to cluster nodes in batches. The default delegate node
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for pushing images is the first kube-master. Note, if you have passwordless sudo
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and docker enabled on the separate admin node, you may want to define the
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``download_localhost: true``, which makes that node a delegate for pushing images
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while running the deployment with ansible. This maybe the case if cluster nodes
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cannot access each over via ssh or you want to use local docker images as a cache
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for multiple clusters.
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* Adjust the `retry_stagger` global var as appropriate. It should provide sane
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load on a delegate (the first K8s master node) then retrying failed
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push or download operations.
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* Tune parameters for DNS related applications (dnsmasq daemon set, kubedns
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replication controller). Those are ``dns_replicas``, ``dns_cpu_limit``,
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``dns_cpu_requests``, ``dns_memory_limit``, ``dns_memory_requests``.
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Please note that limits must always be greater than or equal to requests.
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For example, when deploying 200 nodes, you may want to run ansible with
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``--forks=50``, ``--timeout=600`` and define the ``retry_stagger: 60``.
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