63cd4f5fdc
Incorporated patchset 1 review comments Updated patchset 5 review comments Updated patchset 6 review comments Fixed merge conflicts Updated patchset 8 review comments Change-Id: Icd7b08ab69273f6073b960a13cf59905532f851a Signed-off-by: Juanita-Balaraj <juanita.balaraj@windriver.com>
195 lines
6.0 KiB
ReStructuredText
195 lines
6.0 KiB
ReStructuredText
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.. nos1582114374670
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.. _kubernetes-user-tutorials-mount-readwriteonce-persistent-volumes-in-containers:
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====================================================
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Mount ReadWriteOnce Persistent Volumes in Containers
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====================================================
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You can attach ReadWriteOnce |PVCs| to a container when launching a container,
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and changes to those PVCs will persist even if that container gets terminated
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and restarted.
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.. note::
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A ReadWriteOnce PVC can only be mounted by a single container.
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.. rubric:: |context|
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This example shows how a volume is claimed and mounted by a simple running
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container, and the contents of the volume claim persists across restarts of the
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container. It is the responsibility of an individual micro-service within an
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application to make a volume claim, mount it, and use it.
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.. rubric:: |prereq|
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You should refer to the Volume Claim examples. For more information, see
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:ref:`Create ReadWriteOnce Persistent Volume Claims <storage-configuration-create-readwriteonce-persistent-volume-claims>`.
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.. rubric:: |proc|
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.. _kubernetes-user-tutorials-mounting-persistent-volumes-in-containers-d18e44:
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#. Create the busybox container with the persistent volumes created from the
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|PVCs| mounted.
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#. Create a yaml file definition for the busybox container.
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.. code-block:: none
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% cat <<EOF > rwo-busybox.yaml
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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name: rwo-busybox
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namespace: default
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spec:
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progressDeadlineSeconds: 600
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replicas: 1
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selector:
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matchLabels:
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run: busybox
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template:
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metadata:
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labels:
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run: busybox
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spec:
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containers:
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- args:
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- sh
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image: busybox
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imagePullPolicy: Always
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name: busybox
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stdin: true
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tty: true
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volumeMounts:
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- name: pvc1
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mountPath: "/mnt1"
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- name: pvc2
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mountPath: "/mnt2"
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restartPolicy: Always
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volumes:
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- name: pvc1
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persistentVolumeClaim:
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claimName: rwo-test-claim1
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- name: pvc2
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persistentVolumeClaim:
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claimName: rwo-test-claim2
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EOF
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#. Apply the busybox configuration.
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.. code-block:: none
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% kubectl apply -f rwo-busybox.yaml
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deployment.apps/rwo-busybox created
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#. Attach to the busybox and create files on the persistent volumes.
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#. List the available pods.
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.. code-block:: none
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% kubectl get pods
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NAME READY STATUS RESTARTS AGE
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rwo-busybox-5c4f877455-gkg2s 1/1 Running 0 19s
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#. Connect to the pod shell for CLI access.
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.. code-block:: none
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% kubectl attach rwo-busybox-5c4f877455-gkg2s -c busybox -i -t
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#. From the container's console, list the disks to verify that the
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Persistent Volumes are attached.
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.. code-block:: none
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# df
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Filesystem 1K-blocks Used Available Use% Mounted on
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overlay 31441920 3239984 28201936 10% /
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tmpfs 65536 0 65536 0% /dev
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tmpfs 65900776 0 65900776 0% /sys/fs/cgroup
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/dev/rbd0 999320 2564 980372 0% /mnt1
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/dev/rbd1 999320 2564 980372 0% /mnt2
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/dev/sda4 20027216 4952208 14034624 26%
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...
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The PVCs are mounted as /mnt1 and /mnt2.
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#. Create files in the mounted volumes.
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.. code-block:: none
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# cd /mnt1
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# touch i-was-here
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# ls /mnt1
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i-was-here lost+found
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# cd /mnt2
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# touch i-was-here-too
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# ls /mnt2
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i-was-here-too lost+found
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#. End the container session.
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.. code-block:: none
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# exit
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Session ended, resume using :command:`kubectl attach busybox-5c4f877455-gkg2s -c busybox -i -t`
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when the pod is running
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#. Terminate the busybox container.
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.. code-block:: none
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% kubectl delete -f rwo-busybox.yaml
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#. Re-create the busybox container, again attached to persistent volumes.
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#. Apply the busybox configuration.
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.. code-block:: none
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% kubectl apply -f rwo-busybox.yaml
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deployment.apps/rwo-busybox created
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#. List the available pods.
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.. code-block:: none
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% kubectl get pods
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NAME READY STATUS RESTARTS AGE
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rwo-busybox-5c4f877455-jgcc4 1/1 Running 0 19s
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#. Connect to the pod shell for CLI access.
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.. code-block:: none
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% kubectl attach busybox-5c4f877455-jgcc4 -c busybox -i -t
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#. From the container's console list the disks to verify that the PVCs are attached.
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.. code-block:: none
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# df
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Filesystem 1K-blocks Used Available Use% Mounted on
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overlay 31441920 3239984 28201936 10% /
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tmpfs 65536 0 65536 0% /dev
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tmpfs 65900776 0 65900776 0% /sys/fs/cgroup
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/dev/rbd0 999320 2564 980372 0% /mnt1
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/dev/rbd1 999320 2564 980372 0% /mnt2
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/dev/sda4 20027216 4952208 14034624 26%
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...
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#. Verify that the files created during the earlier container session still exist.
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.. code-block:: none
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# ls /mnt1
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i-was-here lost+found
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# ls /mnt2
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i-was-here-too lost+found
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