5d1fe64bc8
- Update and re-work the documentation:
- Update links
- Fix formatting (especially for lists)
- Remove documentation about `useAlphaApi`,
a flag only for k8s versions < v1.10
- Attempt to clarify the doc
- Update to version 1.5.0
- Remove PodSecurityPolicy (deprecated in k8s v1.21+)
- Update ClusterRole following upstream
(cf https://github.com/kubernetes-sigs/sig-storage-local-static-provisioner/pull/292)
- Add nodeSelector to DaemonSet (following upstream)
131 lines
3.9 KiB
Markdown
131 lines
3.9 KiB
Markdown
# Local Static Storage Provisioner
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The [local static storage provisioner](https://github.com/kubernetes-sigs/sig-storage-local-static-provisioner)
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is NOT a dynamic storage provisioner as you would
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expect from a cloud provider. Instead, it simply creates PersistentVolumes for
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all mounts under the `host_dir` of the specified storage class.
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These storage classes are specified in the `local_volume_provisioner_storage_classes` nested dictionary.
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Example:
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```yaml
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local_volume_provisioner_storage_classes:
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local-storage:
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host_dir: /mnt/disks
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mount_dir: /mnt/disks
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fast-disks:
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host_dir: /mnt/fast-disks
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mount_dir: /mnt/fast-disks
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block_cleaner_command:
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- "/scripts/shred.sh"
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- "2"
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volume_mode: Filesystem
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fs_type: ext4
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```
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For each key in `local_volume_provisioner_storage_classes` a "storage class" with
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the same name is created in the entry `storageClassMap` of the ConfigMap `local-volume-provisioner`.
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The subkeys of each storage class in `local_volume_provisioner_storage_classes`
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are converted to camelCase and added as attributes to the storage class in the
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ConfigMap.
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The result of the above example is:
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```yaml
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data:
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storageClassMap: |
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local-storage:
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hostDir: /mnt/disks
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mountDir: /mnt/disks
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fast-disks:
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hostDir: /mnt/fast-disks
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mountDir: /mnt/fast-disks
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blockCleanerCommand:
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- "/scripts/shred.sh"
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- "2"
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volumeMode: Filesystem
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fsType: ext4
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```
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Additionally, a StorageClass object (`storageclasses.storage.k8s.io`) is also
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created for each storage class:
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```bash
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$ kubectl get storageclasses.storage.k8s.io
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NAME PROVISIONER RECLAIMPOLICY
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fast-disks kubernetes.io/no-provisioner Delete
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local-storage kubernetes.io/no-provisioner Delete
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```
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The default StorageClass is `local-storage` on `/mnt/disks`;
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the rest of this documentation will use that path as an example.
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## Examples to create local storage volumes
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1. Using tmpfs
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```bash
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for vol in vol1 vol2 vol3; do
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mkdir /mnt/disks/$vol
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mount -t tmpfs -o size=5G $vol /mnt/disks/$vol
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done
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```
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The tmpfs method is not recommended for production because the mounts are not
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persistent and data will be deleted on reboot.
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1. Mount physical disks
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```bash
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mkdir /mnt/disks/ssd1
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mount /dev/vdb1 /mnt/disks/ssd1
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```
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Physical disks are recommended for production environments because it offers
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complete isolation in terms of I/O and capacity.
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1. Mount unpartitioned physical devices
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```bash
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for disk in /dev/sdc /dev/sdd /dev/sde; do
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ln -s $disk /mnt/disks
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done
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```
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This saves time of precreating filesystems. Note that your storageclass must have
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`volume_mode` set to `"Filesystem"` and `fs_type` defined. If either is not set, the
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disk will be added as a raw block device.
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1. PersistentVolumes with `volumeMode="Block"`
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Just like above, you can create PersistentVolumes with volumeMode `Block`
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by creating a symbolic link under discovery directory to the block device on
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the node, if you set `volume_mode` to `"Block"`. This will create a volume
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presented into a Pod as a block device, without any filesystem on it.
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1. File-backed sparsefile method
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```bash
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truncate /mnt/disks/disk5 --size 2G
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mkfs.ext4 /mnt/disks/disk5
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mkdir /mnt/disks/vol5
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mount /mnt/disks/disk5 /mnt/disks/vol5
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```
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If you have a development environment and only one disk, this is the best way
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to limit the quota of persistent volumes.
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1. Simple directories
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In a development environment, using `mount --bind` works also, but there is no capacity
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management.
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## Usage notes
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Make sure to make any mounts persist via `/etc/fstab` or with systemd mounts (for
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Flatcar Container Linux or Fedora CoreOS). Pods with persistent volume claims will not be
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able to start if the mounts become unavailable.
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## Further reading
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Refer to the upstream docs here: <https://github.com/kubernetes-sigs/sig-storage-local-static-provisioner>
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