forked from rook/rook
subhamkrai
28cc1ebc55
This commits removes controller-runtime dependencies from the apis dir and to achieve that we are removing webhook. Signed-off-by: subhamkrai <srai@redhat.com>
132 lines
4.6 KiB
Markdown
132 lines
4.6 KiB
Markdown
---
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title: Prerequisites
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---
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Rook can be installed on any existing Kubernetes cluster as long as it meets the minimum version
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and Rook is granted the required privileges (see below for more information).
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## Minimum Version
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Kubernetes **v1.22** or higher is supported.
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## CPU Architecture
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Architectures supported are `amd64 / x86_64` and `arm64`.
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## Ceph Prerequisites
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To configure the Ceph storage cluster, at least one of these local storage types is required:
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* Raw devices (no partitions or formatted filesystems)
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* Raw partitions (no formatted filesystem)
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* LVM Logical Volumes (no formatted filesystem)
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* Persistent Volumes available from a storage class in `block` mode
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Confirm whether the partitions or devices are formatted with filesystems with the following command:
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```console
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$ lsblk -f
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NAME FSTYPE LABEL UUID MOUNTPOINT
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vda
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└─vda1 LVM2_member >eSO50t-GkUV-YKTH-WsGq-hNJY-eKNf-3i07IB
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├─ubuntu--vg-root ext4 c2366f76-6e21-4f10-a8f3-6776212e2fe4 /
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└─ubuntu--vg-swap_1 swap 9492a3dc-ad75-47cd-9596-678e8cf17ff9 [SWAP]
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vdb
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```
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If the `FSTYPE` field is not empty, there is a filesystem on top of the corresponding device. In this example, `vdb` is available to Rook, while `vda` and its partitions have a filesystem and are not available.
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## LVM package
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Ceph OSDs have a dependency on LVM in the following scenarios:
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* If encryption is enabled (`encryptedDevice: "true"` in the cluster CR)
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* A `metadata` device is specified
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* `osdsPerDevice` is greater than 1
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LVM is not required for OSDs in these scenarios:
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* OSDs are created on raw devices or partitions
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* OSDs are created on PVCs using the `storageClassDeviceSets`
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If LVM is required, LVM needs to be available on the hosts where OSDs will be running.
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Some Linux distributions do not ship with the `lvm2` package. This package is required on all storage nodes in the k8s cluster to run Ceph OSDs.
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Without this package even though Rook will be able to successfully create the Ceph OSDs, when a node is rebooted the OSD pods
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running on the restarted node will **fail to start**. Please install LVM using your Linux distribution's package manager. For example:
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**CentOS**:
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```console
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sudo yum install -y lvm2
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```
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**Ubuntu**:
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```console
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sudo apt-get install -y lvm2
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```
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**RancherOS**:
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* Since version [1.5.0](https://github.com/rancher/os/issues/2551) LVM is supported
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* Logical volumes [will not be activated](https://github.com/rook/rook/issues/5027) during the boot process. You need to add an [runcmd command](https://rancher.com/docs/os/v1.x/en/installation/configuration/running-commands/) for that.
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```yaml
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runcmd:
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- [ "vgchange", "-ay" ]
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```
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## Kernel
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### RBD
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Ceph requires a Linux kernel built with the RBD module. Many Linux distributions
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have this module, but not all.
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For example, the GKE Container-Optimised OS (COS) does not have RBD.
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Test your Kubernetes nodes by running `modprobe rbd`.
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If the rbd module is 'not found', rebuild the kernel to include the `rbd` module,
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install a newer kernel, or choose a different Linux distribution.
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Rook's default RBD configuration specifies only the `layering` feature, for
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broad compatibility with older kernels. If your Kubernetes nodes run a 5.4
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or later kernel, additional feature flags can be enabled in the
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storage class. The `fast-diff` and `object-map` features are especially useful.
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```yaml
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imageFeatures: layering,fast-diff,object-map,deep-flatten,exclusive-lock
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```
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### CephFS
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If creating RWX volumes from a Ceph shared file system (CephFS), the recommended minimum kernel version is **4.17**.
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If the kernel version is less than 4.17, the requested PVC sizes will not be enforced. Storage quotas will only be
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enforced on newer kernels.
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## Distro Notes
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Specific configurations for some distributions.
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### NixOS
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For NixOS, the kernel modules will be found in the non-standard path `/run/current-system/kernel-modules/lib/modules/`,
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and they'll be symlinked inside the also non-standard path `/nix`.
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Rook containers require read access to those locations to be able to load the required modules.
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They have to be bind-mounted as volumes in the CephFS and RBD plugin pods.
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If installing Rook with Helm, uncomment these example settings in `values.yaml`:
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* `csi.csiCephFSPluginVolume`
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* `csi.csiCephFSPluginVolumeMount`
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* `csi.csiRBDPluginVolume`
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* `csi.csiRBDPluginVolumeMount`
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If deploying without Helm, add those same values to the settings in the `rook-ceph-operator-config`
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ConfigMap found in operator.yaml:
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* `CSI_CEPHFS_PLUGIN_VOLUME`
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* `CSI_CEPHFS_PLUGIN_VOLUME_MOUNT`
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* `CSI_RBD_PLUGIN_VOLUME`
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* `CSI_RBD_PLUGIN_VOLUME_MOUNT`
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