doc: rephrasing the whole disk requirements section (#1011)

* doc: rephrasing the whole disk requirements section this is an effort to make the disk requirements more clear and also make sure people are aware about the usage of symlinks and poor disk partitioning. * doc: addressing pr comments * Update src/markdown-pages/install-with-kurl/system-requirements.md Co-authored-by: Andrew Lavery <[email protected]> * chore: addressing pr comments --------- Co-authored-by: Andrew Lavery <[email protected]>
replicatedhq · Dec 14, 2023 · b2d3f48 · b2d3f48 · github-actions · Dec 14, 2023
1 parent e245f03
commit b2d3f48
Showing 1 changed file with 15 additions and 43 deletions.
diff --git a/src/markdown-pages/install-with-kurl/system-requirements.md b/src/markdown-pages/install-with-kurl/system-requirements.md
@@ -23,7 +23,7 @@ title: "System Requirements"
 
 * 4 AMD64 CPUs or equivalent per machine
 * 8 GB of RAM per machine
-* 100 GB of Disk Space per machine
+* 256 GB of Disk Space per machine
   *(For more specific requirements see [Disk Space Requirements](#disk-space-requirements) below)*
 * TCP ports 2379, 2380, 6443, 10250, 10257 and 10259 and UDP port 8472 (Flannel VXLAN) open between cluster nodes
   *(For more specific add-on requirements see [Networking Requirements](#networking-requirements) below)*
@@ -47,55 +47,27 @@ For these OSes, the following packages are required per add-on:
 
 ## Disk Space Requirements
 
-### Core Requirements
+### Per Node Disk Space
 
-The following table lists information about the core directory requirements.
+256 GB of disk space per node is strongly recommended to accommodate growth and optimal performance. At minimum, kURL requires 100 GB of disk space per node.
+It is important to note that disk usage can vary based on container image sizes, ephemeral data, and specific application requirements.
 
-| Name           | Location             | Requirements       | Description |
-| -------------- | -------------------- | ------------------ | ----------- |
-| etcd           | /var/lib/etcd/       | 2 GB               | Kubernetes etcd cluster data directory. See the [etcd documentation](https://etcd.io/docs/v3.5/op-guide/hardware/#disks) and [Cloud Disk Performance](#cloud-disk-performance) for more information and recommendations. |
-| kubelet        | /var/lib/kubelet/    | *30 GB &ast;*      | Used for local disk volumes, emptyDir, log storage, and more. See the Kubernetes [Resource Management for Pods and Containers documentation](https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/#local-ephemeral-storage) for more information.  |
-| containerd     | /var/lib/containerd/ | *30 GB &ast;*      | Snapshots, content, metadata for containers and image, as well as any plugin data will be kept in this location. See the [containerd documentation](https://github.com/containerd/containerd/blob/main/docs/ops.md#base-configuration) for more information. |
-| kube-apiserver | /var/log/apiserver/  | 1 GB               | Kubernetes audit logs. See Kubernetes [Auditing documentation](https://kubernetes.io/docs/tasks/debug/debug-cluster/audit/) for mode information. |
-| kURL           | /var/lib/kurl/       | *10 GB &ast;&ast;* | kURL data directory used to store utilities, system packages, and container images. This directory can be overridden with the flag `kurl-install-directory` (see [kURL Advanced Install Options](/docs/install-with-kurl/advanced-options)) |
-| Root Disk      | /                    | 100 GB             | Based on the aggregate requirements above and the fact that Kubernetes will start to reclaim space at 85% full disk, the minimum recommended root partition is 100 GB. See details above for each component. |
+### Storage Provisioner Add-Ons
 
-*&ast; This requirement depends on the size of the container images and the amount of ephemeral data used by your application containers.*
+Informational Note: **OpenEBS** is configured to allocate its Persistent Volumes within the `/var/openebs/local/` directory, signifying that this specific location is utilized for the storage of data by applications that are actively running on the Kurl platform.
 
-*&ast;&ast; This requirement can vary depending on your choice of kURL add-ons and can grow over time.*
+**Rook** add-on, starting from version 1.4.3, requires each node within the cluster to be equipped with an unformatted storage device, which is designated for the storage of Ceph volumes.
+Comprehensive information and guidelines regarding this setup are available in the [Rook Block Storage](https://kurl.sh/docs/add-ons/rook#block-storage) documentation.
+For Rook versions 1.0.x Persistent Volumes are provisioned on `/opt/replicated/rook/` directory.
 
-In addition to the storage requirements, the Kubernetes [garbage collection](https://kubernetes.io/docs/concepts/architecture/garbage-collection/) process attempts to ensure that the Node and Image filesystems do not reach their minimum available disk space [thresholds](https://kubernetes.io/docs/concepts/scheduling-eviction/node-pressure-eviction/#hard-eviction-thresholds) of 10% and 15% respectively.
-For this reason, kURL recommends an additional 20% overhead on top of these disk space requirements for the volume or volumes containing the directories /var/lib/kubelet/ and /var/lib/containerd/.
-For more information see the Kubernetes [Reclaiming node level resources](https://kubernetes.io/docs/concepts/scheduling-eviction/node-pressure-eviction/#reclaim-node-resources) documentation.
+### On Disk Partitioning
 
-### Add-on Requirements
+We advise against configuring the system with multiple mount points.
+Experience has shown that utilizing distinct partitions for directories, such as `/var`, often leads to unnecessary complications.
+Usage of *symbolic links* **is not recommended** in any scenario.
 
-The following table lists the add-on directory locations and disk space requirements, if applicable. For any additional requirements, see the specific topic for the add-on.
-
-| Name     | Location             | Requirements  | Description |
-| -------- | -------------------- | ------------- | ----------- |
-| Docker   | /var/lib/docker/     | *30 GB &ast;* | Images, containers and volumes, and more will be kept in this location. See the [Docker Storage documentation](https://docs.docker.com/storage/) for more information. When using the Docker runtime, /var/lib/containerd/ is not required. |
-| Docker   | /var/lib/dockershim/ | N/A           | Kubernetes dockershim data directory |
-| Weave    | /var/lib/cni/        | N/A           | Container networking data directory |
-| Weave    | /var/lib/weave/      | N/A           | Weave data directory |
-| Rook     | /var/lib/rook/       | 10 GB         | Ceph monitor metadata directory. See the [ceph-mon Minimum Hardware Recommendations](https://docs.ceph.com/en/quincy/start/hardware-recommendations/#minimum-hardware-recommendations) for more information. |
-| Registry | *PVC &ast;&ast;*     | N/A           | Stores container images only in airgapped clusters. Data will be stored in Persistent Volumes. |
-| Velero   | *PVC &ast;&ast;*     | N/A           | Stores snapshot data. Data will be stored in Persistent Volumes. |
-
-*&ast; This requirement depends on the size of the container images and the amount of ephemeral data used by your application containers.*
-
-*&ast;&ast; Data will be stored in Persistent Volumes. Requirements depend on the provisioner of choice. See [Persistent Volume Requirements](#persistent-volume-requirements) for more information.*
-
-### Persistent Volume Requirements
-
-Depending on the amount of persistent data stored by your application, you will need to allocate enough disk space at the following location dependent on your PVC provisioner or provisioners.
-
-| Name                 | Location              | Description |
-| -------------------- | --------------------- | ----------- |
-| OpenEBS              | /var/openebs/local/   | OpenEBS Local PV Hostpath volumes will be created under this directory. See the [OpenEBS Add-on](/docs/add-ons/openebs) documentation for more information. |
-| Rook (Block Storage) |                       | Rook add-on version 1.4.3 and later requires an unformatted storage device on each node in the cluster for Ceph volumes. See the [Rook Block Storage](/docs/add-ons/rook#block-storage) documentation for more information. |
-| Rook (version 1.0.x) | /opt/replicated/rook/ | Rook Filesystem volumes will be created under this directory. See the [Rook Filesystem Storage](/docs/add-ons/rook#filesystem-storage) documentation for more information. |
-| Longhorn             | /var/lib/longhorn/    | Longhorn volumes will be created under this directory. See the [Longhorn Add-on](/docs/add-ons/longhorn) documentation for more information. |
+Should it be required, the directories utilized by the selected Storage Provisioner (for example, `/var/openebs/local` in the case of OpenEBS) can be set up to mount from a separate partition.
+This configuration should be established **prior to the installation**. It's important to emphasize that Storage Provisioners are not compatible with *symbolic links*.
 
 ## Networking Requirements