f125a8b892
This change addresses a long-standing issue in rST documentation imported from XML.
That import process added backslash escapes in front of various characters. The three
most common being '(', ')', and '_'.
These instances are removed.
Signed-off-by: Ron Stone <ronald.stone@windriver.com>
Change-Id: Id43a9337ffcd505ccbdf072d7b29afdb5d2c997e
4.3 KiB
Executable File
Storage Resources
uses storage resources on the controller and worker hosts, and on storage hosts if they are present.
The storage configuration is highly flexible. The specific configuration depends on the type of system installed, and the requirements of the system.
Uses of Disk Storage
- System
-
The system uses root disk storage for the operating system and related files, and for internal databases. On controller nodes, the database storage and selected root file-systems are synchronized between the controller nodes using .
- Local Docker Registry
-
An HA local docker registry is deployed on controller nodes to provide local centralized storage of container images. Its image store is a synchronized file system.
- Docker Container Images
-
Container images are pulled from either a remote or local Docker Registry, and cached locally by docker on the host worker or controller node when a container is launched.
- Container Ephemeral Local Disk
-
Containers have local filesystems for ephemeral storage of data. This data is lost when the container is terminated.
Kubernetes Docker ephemeral storage is allocated as part of the docker-lv and kubelet-lv file systems from the cgts-vg volume group on the root disk. These filesystems are resizable.
- Container Persistent Volume Claims (PVCs)
-
Containers can mount remote HA replicated volumes backed by the Ceph Storage Cluster for managing persistent data. This data survives restarts of the container.
Note
Ceph is not configured by default.
Storage Locations
In addition to the root disks present on each host for system storage, the following storage may be used only for:
- Controller hosts: on dedicated storage hosts when using that setup or on controller hosts. Additional Ceph disk(s) are present on controllers in configurations without dedicated storage hosts. These provide storage to fill made by Kubernetes pods or containers.
- Worker hosts: This is storage is derived from docker-lv/kubelet-lv as defined on the cgts-vg (root disk). You can add a disk to cgts-vg and increase the size of the docker-lv/kubelet-lv.
- Combined Controller-Worker Hosts
-
One or more disks can be used on combined hosts in Simplex or Duplex systems to provide local ephemeral storage for containers, and a Ceph cluster for backing Persistent Volume Claims.
Container/Pod ephemeral storage is implemented on the root disk on all controllers/workers regardless of labeling.
- Storage Hosts
-
One or more disks are used on storage hosts to realize a large scale Ceph cluster providing backing for for containers. Storage hosts are used only on with Dedicated Storage systems.
External Netapp Trident
can be configured to connect-to and use an external Netapp Trident deployment as its storage backend.
Netapp Trident supports:
- Cloud Volumes
- E and EF-Series SANtricity
- ONTAP AFF, FAS, Select, and Cloud
- Element HCI and SolidFire
- Azure NetApp Files service
For more information about Trident, see https://netapp-trident.readthedocs.io.
Storage on Controller Hosts <storage-planning-storage-on-controller-hosts>
Storage on Worker Hosts <storage-planning-storage-on-worker-hosts>
Storage on Storage Hosts <storage-planning-storage-on-storage-hosts>