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(DOCSP-9072): Allow PodSpecTemplate for containers to modify the cont… (#219)
* (DOCSP-9072): Allow PodSpecTemplate for containers to modify the container spec and also provide side-car design * (DOCSP-9072): copy review feedback * (DOCSP-9072): tech review feedback
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‎config/redirects‎

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@@ -50,3 +50,4 @@ raw: kubernetes-operator/release-notes -> ${base}/stable/release-notes
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# v1.3 and earlier
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[*-v1.3]: kubernetes-operator/${version}/tutorial/plan-k8s-operator-install -> ${base}/${version}/tutorial/install-k8s-operator
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[*-v1.3]: kubernetes-operator/${version}/tutorial/modify-resource-image -> ${base}/${version}/

‎source/index.txt‎

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Install the Operator </installation>
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Deploy Ops Manager Resources </om-resources>
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Deploy MongoDB Database Resources </mdb-resources>
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/tutorial/modify-resource-image
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/reference
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/specification
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Release Notes </release-notes>

‎source/reference/troubleshooting.txt‎

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further changes through the |onprem| application. However, the
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|k8s-op-short| retains any changes you made in the |onprem|
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application while features were available.
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Tune MongoDB |k8s| Resource Docker Images
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-----------------------------------------
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|k8s-mdbrsc| Docker images run on Ubuntu and use Ubuntu's default
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system configuration. Using the :setting:`spec.podSpec.podTemplate`
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setting, add a privileged sidecar :k8sdocs:`init container
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</concepts/workloads/pods/init-containers/>` to the |k8s-mdbrsc|
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definition to tune the underlying Ubuntu system configuration in the
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|k8s-mdbrsc| containers.
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.. example::
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|k8s-mdbrsc| Docker images use the Ubuntu default ``keepalive`` time
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of ``7200``. MongoDB recommends a shorter ``keepalive`` time of ``120``
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for database deployments.
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You can tune the ``keepalive`` time in the |k8s-mdbrscs| Docker images
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if you experience network timeouts or socket errors in communication
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between clients and |k8s-mdbrscs|.
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To tune |k8s-mdbrsc| Docker images:
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1. Update the |k8s-mdbrsc| definition to append a privileged sidecar
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container to |k8s-mdbrsc| pods the |k8s-op-short| creates.
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The following sample :setting:`spec.podSpec.podTemplate` changes the
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``keepalive`` value to the recommended value of ``120``:
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.. code-block:: yaml
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spec:
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podSpec:
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podTemplate:
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spec:
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initContainers:
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- name: "apply-sysctl-test"
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image: "busybox:latest"
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securityContext:
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privileged: true
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command: ["sysctl", "-w", "net.ipv4.tcp_keepalive_time=120"]
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#. Apply the updated resource definition:
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.. code-block:: none
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kubectl apply -f <database-resource-conf>.yaml -n <namespace>
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A privileged sidecar container is added to each |k8s-pod| the
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|k8s-op-short| created using the |k8s-mdbrsc| definition.
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To verify your changes:
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1. Get a shell to a running container in your database resource
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|k8s-pod|:
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.. code-block:: none
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kubectl exec -n <namespace> -it <pod-name> -- /bin/bash
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#. Verify your changes are present. Following the example, verify that
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the ``keepalive`` time is changed:
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.. code-block:: none
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cat /proc/sys/net/ipv4/tcp_keepalive_time
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Returns:
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.. code-block:: none
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:copyable: false
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120
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.. seealso:: :manual:`Operating System Configuration </administration/production-checklist-operations/#linux>` in the MongoDB Manual.

‎source/tutorial/modify-resource-image.txt‎

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.. _modify-resource-image:
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=========================================================
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Modify |onprem| or MongoDB Kubernetes Resource Containers
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=========================================================
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.. default-domain:: mongodb
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.. contents:: On this page
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:local:
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:backlinks: none
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:depth: 1
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:class: singlecol
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You can modify the containers in the |k8s-pods| in which |onprem| and
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|k8s-mdbrscs| run using the ``podTemplate`` setting that applies to your
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deployment:
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- |onprem|: :opsmgrkube:`spec.podSpec.podTemplate`
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- MongoDB database: :setting:`spec.podSpec.podTemplate`
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To review which fields you can add to a ``podTemplate``, see the
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:k8sdocs:`Kubernetes documentation
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</reference/generated/kubernetes-api/v1.11/#podspec-v1-core>`.
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When you create containers using a ``podTemplate``, the |k8s-op-short|
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handles container creation differently based on the ``name`` you provide
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for each container in the ``containers`` array:
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- If the ``name`` field *matches* the name of the applicable resource
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image, the |k8s-op-short| updates the |onprem| or MongoDB database
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container in the |k8s-pod| to which the ``podTemplate`` applies:
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- |onprem|: ``mongodb-enterprise-ops-manager``
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- MongoDB database: ``mongodb-enterprise-database``
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- If the ``name`` field *does not match* the name of the applicable
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resource image, the |k8s-op-short| creates an InitContainer in each
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|k8s-pod| to which the ``podTemplate`` applies.
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Define a Volume Mount for a MongoDB Kubernetes Resource
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-------------------------------------------------------
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On-disk files in containers in |k8s-pods| don't survive container
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crashes or restarts. Using the :setting:`spec.podSpec.podTemplate`
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setting, you can add a :k8sdocs:`volume mount
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</concepts/storage/volumes/>` to persist data for the life of the
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|k8s-pod|.
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To create a volume mount:
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1. Update the |k8s-mdbrsc| definition to include a volume mount for
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containers in the |k8s-mdbrsc| pods the |k8s-op-short| creates.
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The following sample :setting:`spec.podSpec.podTemplate` defines
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a volume mount:
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.. code-block:: yaml
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podSpec:
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podTemplate:
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spec:
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containers:
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- name: mongod-enterprise-database
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volumeMounts:
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- mountPath: /data
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name: survives-restart
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volumes:
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- name: survives-restart
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emptyDir: {}
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#. Apply the updated resource definition:
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.. code-block:: none
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kubectl apply -f <database-resource-conf>.yaml -n <namespace>
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Tune MongoDB MongoDB Kubernetes Resource Docker Images with an InitContainer
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----------------------------------------------------------------------------
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|k8s-mdbrsc| Docker images run on Ubuntu and use Ubuntu's default
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system configuration. To tune the underlying Ubuntu system configuration
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in the |k8s-mdbrsc| containers, use the :setting:`spec.podSpec.podTemplate`
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setting to add a privileged InitContainer :k8sdocs:`init container
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</concepts/workloads/pods/init-containers/>` to the |k8s-mdbrsc|
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definition.
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.. example::
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|k8s-mdbrsc| Docker images use the Ubuntu default ``keepalive`` time
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of ``7200``. MongoDB recommends a shorter ``keepalive`` time of ``120``
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for database deployments.
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You can tune the ``keepalive`` time in the |k8s-mdbrscs| Docker images
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if you experience network timeouts or socket errors in communication
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between clients and |k8s-mdbrscs|.
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.. seealso:: :manual:`Does TCP keepalive time affect MongoDB Deployments? </faq/diagnostics/#does-tcp-keepalive-time-affect-mongodb-deployments>` in the MongoDB Manual
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To tune |k8s-mdbrsc| Docker images:
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1. Update the |k8s-mdbrsc| definition to append a privileged
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InitContainer to |k8s-mdbrsc| pods the |k8s-op-short| creates.
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The following sample :setting:`spec.podSpec.podTemplate` changes the
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``keepalive`` value to the recommended value of ``120``:
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.. code-block:: yaml
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spec:
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podSpec:
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podTemplate:
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spec:
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initContainers:
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- name: "adjust-tcp-keepalive"
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image: "busybox:latest"
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securityContext:
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privileged: true
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command: ["sysctl", "-w", "net.ipv4.tcp_keepalive_time=120"]
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#. Apply the updated resource definition:
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.. code-block:: none
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kubectl apply -f <database-resource-conf>.yaml -n <namespace>
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A privileged InitContainer is added to each |k8s-pod| the |k8s-op-short|
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creates using the |k8s-mdbrsc| definition.
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Open a shell session to a running container in your database resource
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|k8s-pod| and verify your changes. For the ``keepalive`` example above,
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use the following command to get the current ``keepalive`` value:
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.. code-block:: none
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kubectl exec -n <namespace> -it <pod-name> -- cat /proc/sys/net/ipv4/tcp_keepalive_time
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Returns:
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.. code-block:: none
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:copyable: false
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120
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.. seealso:: :manual:`Operating System Configuration </administration/production-checklist-operations/#linux>` in the MongoDB Manual.

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