CCE Container Storage (Everest)

Introduction

Everest is a cloud native container storage system, which enables clusters of Kubernetes v1.15.6 or later to access cloud storage services through the CSI.

Everest is a system resource add-on. It is installed by default when a cluster of Kubernetes v1.15 or later is created.

Constraints

• If your cluster is upgraded from v1.13 to v1.15, storage-driver will be replaced by Everest (v1.1.6 or later) for container storage. The takeover does not affect the original storage functions.
• In version 1.2.0 of the Everest add-on, key authentication is optimized when OBS is used. After the Everest add-on is upgraded from a version earlier than 1.2.0, restart all workloads that use OBS in the cluster. Otherwise, workloads may not be able to use OBS.
• By default, this add-on is installed in clusters of v1.15 and later. For clusters of v1.13 and earlier, the storage-driver add-on is installed by default.

Installing the Add-on

This add-on has been installed by default. If it is uninstalled due to some reasons, you can reinstall it by performing the following steps:

1. Log in to the CCE console and click the cluster name to access the cluster console. Click Add-ons in the navigation pane, locate CCE Container Storage (Everest) on the right, and click Install.
2. On the Install Add-on page, configure the specifications.

   Table 1 Everest parameters

   Parameter	Description
   Pods	Number of pods for the add-on. High availability is not possible with a single pod. If an error occurs on the node where the add-on instance runs, the add-on will fail.
   Containers	The Everest add-on contains the Everest-csi-controller and everest-csi-driver components. For details, see Components. The add-on component specifications can be customized based on your requirements. Retain the default requested CPU and memory values of the add-on components. The limit values can be adjusted based on the number of cluster nodes and PVCs. For details about the configuration suggestions, see Table 2. In non-typical scenarios, the formulas for estimating the limit values are as follows: everest-csi-controller CPU limit: 250m for 200 or fewer nodes, 350m for 1000 nodes, and 500m for 2000 nodes Memory limit = (200 Mi + Number of nodes x 1 Mi + Number of PVCs x 0.2 Mi) x 1.2 everest-csi-driver CPU limit: 300m for 200 or fewer nodes, 500m for 1000 nodes, and 800m for 2000 nodes Memory limit: 300 Mi for 200 or fewer nodes, 600 Mi for 1000 nodes, and 900 Mi for 2000 nodes

   Table 2 Recommended configuration limits in typical scenarios

   Configuration Scenario			everest-csi-controller		everest-csi-driver
   Nodes	PVs/PVCs	Add-on Instances	vCPUs (Limit = Requested)	Memory (Limit = Requested)	vCPUs (Limit = Requested)	Memory (Limit = Requested)
   50	1000	2	250m	600 MiB	300m	300 MiB
   200	1000	2	250m	1 GiB	300m	300 MiB
   1000	1000	2	350m	2 GiB	500m	600 MiB
   1000	5000	2	450m	3 GiB	500m	600 MiB
   2000	5000	2	550m	4 GiB	800m	900 MiB
   2000	10000	2	650m	5 GiB	800m	900 MiB

3. Configure the add-on parameters.

   Table 3 Everest parameters

   Parameter	Description
   csi_attacher_worker_threads	Number of worker nodes that can be concurrently processed by Everest for attaching EVS volumes. The default value is 60.
   csi_attacher_detach_worker_threads	Number of worker nodes that can be concurrently processed by Everest for detaching EVS volumes. The default value is 60.
   volume_attaching_flow_ctrl	Maximum number of EVS volumes that can be attached by the Everest add-on within 1 minute. The default value is 0, indicating that the performance of attaching EVS volumes is determined by the underlying storage resources.
   cluster_id	Cluster ID
   default_vpc_id	ID of the VPC to which the cluster belongs
   disable_auto_mount_secret	Whether the default AK/SK can be used when an object bucket or parallel file system is mounted. The default value is false.
   enable_node_attacher	Whether to enable the attacher on the agent to process the VolumeAttachment.
   flow_control	This field is left blank by default. You do not need to configure this parameter.
   number_of_reserved_disks	Number of disks on the node reserved for custom use. This parameter is supported when the add-on version is 2.3.11 or later. Assume that a maximum of 20 EVS disks can be attached to a node, and the value of this parameter is set to 6. Then 14 (20-6) disks can be attached to this node when the system schedules the EVS disk attachment workloads. The reserved six disks include one system disk and one data disk that has been attached to the node. You can attach four EVS disks to this node as additional data disks or raw disks for a local storage pool.
   over_subscription	Overcommitment ratio of the local storage pool (local_storage). The default value is 80. If the size of the local storage pool is 100 GB, it can be overcommitted to 180 GB.
   project_id	ID of the project to which a cluster belongs

   

   In Everest 1.2.26 or later, the performance of attaching a large number of EVS volumes has been optimized. The following parameters can be configured:

   • csi_attacher_worker_threads
   • csi_attacher_detach_worker_threads
   • volume_attaching_flow_ctrl

   The preceding parameters are associated with each other and are constrained by the underlying storage resources in the region where the cluster is located. To attach a large number of volumes (more than 500 EVS volumes per minute), contact administrator and configure the parameters under their guidance to prevent the Everest add-on from running abnormally due to improper parameter settings.

4. Configure scheduling policies for the add-on.
   

   • Scheduling policies do not take effect on add-on instances of the DaemonSet type.
   • When configuring multi-AZ deployment or node affinity, ensure that there are nodes meeting the scheduling policy and that resources are sufficient in the cluster. Otherwise, the add-on cannot run.

   Table 4 Configurations for add-on scheduling

   Parameter	Description
   Multi AZ	Preferred: Deployment pods of the add-on will be preferentially scheduled to nodes in different AZs. If all the nodes in the cluster are deployed in the same AZ, the pods will be scheduled to that AZ. Equivalent mode: Deployment pods of the add-on are evenly scheduled to the nodes in the cluster in each AZ. If a new AZ is added, you are advised to increase add-on pods for cross-AZ HA deployment. With the Equivalent multi-AZ deployment, the difference between the number of add-on pods in different AZs will be less than or equal to 1. If resources in one of the AZs are insufficient, pods cannot be scheduled to that AZ. Required: Deployment pods of the add-on will be forcibly scheduled to nodes in different AZs. If there are fewer AZs than pods, the extra pods will fail to run.
   Node Affinity	Not configured: Node affinity is disabled for the add-on. Node Affinity: Specify the nodes where the add-on is deployed. If you do not specify the nodes, the add-on will be randomly scheduled based on the default cluster scheduling policy. Specified Node Pool Scheduling: Specify the node pool where the add-on is deployed. If you do not specify the node pool, the add-on will be randomly scheduled based on the default cluster scheduling policy. Custom Policies: Enter the labels of the nodes where the add-on is to be deployed for more flexible scheduling policies. If you do not specify node labels, the add-on will be randomly scheduled based on the default cluster scheduling policy. If multiple custom affinity policies are configured, ensure that there are nodes that meet all the affinity policies in the cluster. Otherwise, the add-on cannot run.
   Toleration	Using both taints and tolerations allows (not forcibly) the add-on Deployment to be scheduled to a node with the matching taints, and controls the Deployment eviction policies after the node where the Deployment is located is tainted. The add-on adds the default tolerance policy for the node.kubernetes.io/not-ready and node.kubernetes.io/unreachable taints, respectively. The tolerance time window is 60s. For details, see Taints and Tolerations.

5. Click Install.

Components