Installing OpenEBS
Summary:
Verify if iSCSI client is running
Set Kubernetes admin context and RBAC
Installation
- helm chart
(or) - kubectl yaml spec file
- helm chart
Verify installation
Installation troubleshooting
Verify iSCSI client
iSCSI client is a pre-requisite for provisioning cStor and Jiva volumes. However, it is recommended that the iSCSI client is setup and iscsid service is running on worker nodes before proceeding with the OpenEBS installation.
Set cluster-admin user context and RBAC
For installation of OpenEBS, cluster-admin user context is a must.
If there is no cluster-admin user context already present, create one and use it. Use the following command to create the new context.
kubectl config set-context NAME [--cluster=cluster_nickname] [--user=user_nickname] [--namespace=namespace]
Example:
kubectl config set-context admin-ctx --cluster=gke_strong-eon-153112_us-central1-a_rocket-test2 --user=cluster-admin
Set the existing cluster-admin user context or the newly created context by using the following command.
Example:
kubectl config use-context admin-ctx
Installation through helm
Verify helm is installed and helm repo is updated.
For Helm v2
Run helm init for installing tiller pod under kube-system namespace.
See instructions below for setting up RBAC for tiller.
Installed helm version can be obtained by using the following command:
helm version
Example ouptut:
In the default installation mode, use the following command to install the latest version of OpenEBS in openebs namespace.
helm repo add openebs https://openebs.github.io/charts
helm repo update
helm install --namespace openebs --name openebs openebs/openebs
For Helm v3
See helm docs for setting up helm v3. Installed helm version can be obtained by using the following command:
helm version
Example ouptut:
OpenEBS instalaltion with helm v3 can be done by 2 ways:
Option 1: Helm v3 takes the current namespace from the local kube config and use that namespace the next time the user executes helm commands. If it is not present, the default namespace is used. Assign the openebs namespace to the current context and run the following commands to install openebs in openebs namespace.
To view current context, run the following:
kubectl config current-context
Assign openebs namespace to the current context:
kubectl config set-context <current_context_name> --namespace=openebs
Create OpenEBS namespace
kubectl create ns openebs
Install openebs with chart name as openebs:
helm repo add openebs https://openebs.github.io/charts
helm repo update
helm install openebs openebs/openebs
To view the chart
helm ls
The above commands will install OpenEBS in openebs namespace and chart name as openebs
Option 2: By mentioning namespace in helm command
Create OpenEBS namespace
kubectl create ns openebs
Install openebs with chart name as openebs:
helm repo add openebs https://openebs.github.io/charts
helm repo update
helm install --namespace openebs openebs openebs/openebs
To view the chart
helm ls -n openebs
The above commans will install OpenEBS in openebs namespace and chart name as openebs
Note:
Since Kubernetes 1.12, if any containers does not set its resource requests & limits values, it results into eviction. It is recommended to set these values appropriately to OpenEBS pod spec in the operator YAML before installing OpenEBS. The example configuration can be obtained from here.
Check the blockdevice mount status on Nodes before installing OpenEBS operator. More details can be obtained here.
As a next step verify your installation and do the post installation steps.
In the custom installation mode, you can achieve the following advanced configurations
- Choose a set of nodes for OpenEBS control plane pods.
- Choose a set of nodes for OpenEBS storage pool.
- You can customize the disk filters that need to be excluded from being used.
- You can choose custom namespace other than default namespace
openebs.
Follow the below instructions to do any of the above configurations and then install OpenEBS through helm and values.yaml
Setup nodeSelectors for OpenEBS control plane
In a large Kubernetes cluster, you may choose to limit the scheduling of the OpenEBS control plane pods to two or three specific nodes. To do this, use nodeSelector field of PodSpec of OpenEBS control plane pods - apiserver, volume provisioner,admission-controller and snapshot operator.
See the example here.
Setup nodeSelectors for Node Disk Manager (NDM)
OpenEBS cStorPool is constructed using the disk custom resources or disk CRs created by Node Disk Manager or NDM. If you want to consider only some nodes in Kubernetes cluster to be used for OpenEBS storage (for hosting cStor Storage Pool instances), then use nodeSelector field of NDM PodSpec and dedicate those nodes to NDM.
See an example here.
Setup disk filters for Node Disk Manager
NDM by default filters out the below disk patterns and converts the rest of the disks discovered on a given node into DISK CRs as long as they are not mounted.
"exclude":"loop,/dev/fd0,/dev/sr0,/dev/ram,/dev/dm-"
If your cluster nodes have different disk types that are to be filtered out (meaning that those should not be created as DISK CRs ), add the additional disk patterns to the exclude list.
See an example configuration here
Other values.yaml parameters
For customized configuration through helm, use values.yaml or command line parameters.
Default values for Helm Chart parameters are provided below.
After doing the custom configuration in the values.yaml file, run the below command to do the custom installation.
helm install --namespace <custom_namespace> --name openebs openebs/openebs -f values.yaml
As a next step verify your installation and do the post installation steps.
Installation through kubectl
In the default installation mode, use the following command to install OpenEBS. OpenEBS is installed in openebs namespace.
kubectl apply -f https://openebs.github.io/charts/openebs-operator.yaml
Note:
Since Kubernetes 1.12, if any pod containers does not set its resource requests & limits values, it results into eviction. It is recommend to set these values appropriately to OpenEBS pod spec in the operator YAML before installing OpenEBS. The example configuration can be get from here.
Check the blockdevice mount status on Nodes before installing OpenEBS operator. More details can be obtained here.
As a next step verify your installation and do the post installation steps.
In the custom installation mode, you can achieve the following advanced configurations.
- Choose a set of nodes for OpenEBS control plane pods
- Choose a set of nodes for OpenEBS storage pool
- You can customize the disk filters that need to be excluded from being used
- (Optional) Configure with Environment Variables in OpenEBS operator YAML
For custom installation, download the openebs-operator YAML file, update the above configurations using the instructions below and proceed to installation with kubectl command.
Setup nodeSelectors for OpenEBS control plane
In a large Kubernetes cluster, you may choose to limit the scheduling of the OpenEBS control plane pods to two or three specific nodes. To do this, specify a map of key-value pair and then attach the same key-value pair as labels to the required nodes on the cluster.
Example nodeSelector configuration for OpenEBS control plane components is given here.
Setup nodeSelectors for Admission Controller
The Admission controller to intercepts the requests to the Kubernetes API server prior to persistence of the object, but after the request is authenticated and authorized. This openebs admission controller implements additional custom admission policies to validate the incoming request. The following are the admission policies available with the latest main release.
- PersistentVolumeClaim delete requests validates if there is clone PersistentVolumeClaim exists.
- Clone PersistentVolumeClaim create requests validates requested claim capacity. This has to be equal to snapshot size.
The Admission Controller pod can be scheduled on particular node using nodeSelector method.
Example nodeSelector configuration for OpenEBS control plane components is given here.
Setup nodeSelectors for Node Disk Manager (NDM)
OpenEBS cStorPool is constructed using the block device custom resources or block device created by Node Disk Manager or NDM. If you want to consider only some nodes in Kubernetes cluster to be used for OpenEBS storage (for hosting cStor Storage Pool instances), then specify a map of key-value pair and then attach the same key-value pair as labels to the required nodes on the cluster.
Example nodeSelector configuration for OpenEBS control plane components is given here.
Setup disk filters for Node Disk Manager
NDM by default filters out the below disk patterns and converts the rest of the disks discovered on a given node into DISK CRs as long as they are not mounted.
"exclude":"loop,/dev/fd0,/dev/sr0,/dev/ram,/dev/dm-"
If your cluster nodes have different disk types that are to be filtered out (meaning that those should not be created as DISK CRs ), add the additional disk patterns to the exclude list in the yaml file.
See an example configuration here
Configure with Environment Variables
Some of the configurations related to cStor Target, default cStor sparse pool, default Storage configuration, Local PV Basepath, etc can be configured as variables in the corresponding deployment specification.
Enable core dump
Dumping cores has been disabled by default for cStor pool and NDM daemonset pods. This can be enabled by setting an ENV variable ENABLE_COREDUMP to 1. The ENV setting can be added in cStor pool deployment for dumping core for cStor pool pod and the ENV setting can be added in ndm daemonset spec for dumping core for ndm daemonset pods.
- name: ENABLE_COREDUMP
value: "1"
SparseDir
SparseDir is a hostPath directory where to look for sparse files. The default value is "/var/openebs/sparse".
The following configuration must added as environment variables in the maya-apiserver deployment specification. This change must be done before applying the OpenEBS operator YAML file.
# environment variable
- name: SparseDir
value: "/var/lib/"
Default cStorSparsePool
The OpenEBS installation will create default cStor sparse pool based on this configuration value. If "true", default cStor sparse pools will be configured, if "false", it will not be configure a default cStor sparse pool. The default configured value is "false". The use of cStor sparse pool is for testing purposes only.
The following configuration must be added as environment variables in the maya-apiserver deployment specification for the installation of cStor pool using sparse disks. This change must be done before applying the OpenEBS operator YAML file.
Example:
# environment variable
- name: OPENEBS_IO_INSTALL_DEFAULT_CSTOR_SPARSE_POOL
value: "false"
TargetDir
Target Dir is a hostPath directory for target pod. The default value is "/var/openebs". This value can override the existing host path introducing a OPENEBS_IO_CSTOR_TARGET_DIR ENV in maya-apiserver deployment. This configuration might required where underlying host OS does not have write permission on default OpenEBS path(/var/openebs/).
The following configuration must added as environment variables in the maya-apiserver deployment specification. This change must be done before applying the OpenEBS operator YAML file.
Example:
# environment variable
- name: OPENEBS_IO_CSTOR_TARGET_DIR
value: "/var/lib/overlay/openebs"
Basepath for OpenEBS Local PV
By default the hostpath is configured as /var/openebs/local for Local PV based on hostpath, which can be changed during the OpenEBS operator install by passing the OPENEBS_IO_BASE_PATH ENV parameter to the Local PV dynamic provisioner deployment.
# environment variable
- name: OPENEBS_IO_BASE_PATH
value: "/mnt/"
Default Storage Configuration
OpenEBS comes with default storage configuration like Jiva and Local PV storage classes and so forth. Each of the storage engines in OpenEBS is highly configurable and the customization is done via Storage Classes and associated Custom Resources. While the default storage configuration can be modified after installation, it is going to be overwritten by the OpenEBS API Server. The recommended approach for customizing is to have users create their own storage configuration using the default options as examples/guidance.
If you would like to use a customized configuration, you can disable the installation of the default storage configuration during the installation. The following configuration must be added as environment variables in the maya-apiserver deployment specification to disable default storage configuration.
# environment variable
- name: OPENEBS_IO_CREATE_DEFAULT_STORAGE_CONFIG
value: "false"
Note: Starting with 0.9, cStor Sparse pool and its Storage Class are not created by default. If you need to enable the cStor Sparse pool for development or test environments, you should have the above Default Storage Configuration enabled as well as cStor sparse pool enabled using the instructions mentioned here.
After doing the custom configuration in the downloaded openebs-operator.yaml file, run the below command to do the custom installation.
kubectl apply -f <modified openebs-operator.yaml>
As a next step verify your installation and do the post installation steps.
Verifying OpenEBS installation
Verify pods:
List the pods in <openebs> name space
kubectl get pods -n openebs
In the successful installation of OpenEBS, you should see an example output like below.
openebs-ndm is a daemon set, it should be running on all nodes or on the nodes that are selected through nodeSelector configuration.
The control plane pods openebs-provisioner, maya-apiserver and openebs-snapshot-operator should be running. If you have configured nodeSelectors , check if they are scheduled on the appropriate nodes by listing the pods through kubectl get pods -n openebs -o wide
The resiliency of the control plane can be verified via
litmususing openebs-control-plane-chaos experiment.
Verify StorageClasses:
List the storage classes to check if OpenEBS has installed with default StorageClasses.
kubectl get sc
In the successful installation, you should have the following StorageClasses are created.
Verify Block Device CRs
NDM daemon set creates a block device CR for each block devices that is discovered on the node with two exceptions
- The disks that match the exclusions in 'vendor-filter' and 'path-filter'
- The disks that are already mounted in the node
List the block device CRs to verify the CRs are appearing as expected.
kubectl get blockdevice -n openebs
Following is an example output.
To know which block device CR belongs to which node, check the node label set on the CR by doing the following command.
kubectl describe blockdevice <blockdevice-cr> -n openebs
Verify Jiva default pool - default
kubectl get sp
Following is an example output.
Post-Installation considerations
For a simple testing of OpenEBS, you can use the below default storage classes
openebs-jiva-defaultfor provisioning Jiva Volume (this usesdefaultpool which means the data replicas are created in the /mnt/openebs_disk directory of the Jiva replica pod)openebs-hostpathfor provisioning Local PV on hostpath.openebs-devicefor provisioning Local PV on device.
For using real disks, you have to create cStorPools or Jiva pools or OpenEBS Local PV based on the requirement and then create corresponding StorageClasses or use default StorageClasses to use them.
Example configuration- Pod resource requests
All openebs components should have ephemeral storage requests set against each of its pod containers and side cars. Ephemeral storage requests can be used only from Kubernetes 1.13 or in earlier versions if the feature-gate flag is enabled. This value should be added for all the openebs control plane components in the openebs operator YAML file before applying it. This setting is used to specify ephemeral-storage to avoid erroneous eviction by K8s.
The following is one the example configurations for AuxResourceRequests which allow you to set requests on side cars of the container.
AuxResourceRequests
This setting is useful in cases where user has to specify minimum ephemeral-storage requests to avoid erroneous eviction by K8s. The below spec will set the side-cars with 50Mi ephemeral-storage requests.
- name: AuxResourceRequests
value: |-
ephemeral-storage: "50Mi"
Example configurations - helm
Setup RBAC for Tiller before Installing OpenEBS Chart
kubectl -n kube-system create sa tiller
kubectl create clusterrolebinding tiller --clusterrole cluster-admin --serviceaccount=kube-system:tiller
kubectl -n kube-system patch deploy/tiller-deploy -p '{"spec": {"template": {"spec": {"serviceAccountName": "tiller"}}}}'
kubectl -n kube-system patch deployment tiller-deploy -p '{"spec": {"template": {"spec": {"automountServiceAccountToken": true}}}}'
Ensure that helm repo in your master node is updated to get the latest OpenEBS repository using the following command
helm repo update
For nodeSelectors in values.yaml (helm)
First, label the required nodes with an appropriate label. In the following command, the required nodes for storage nodes are labelled as node=openebskubectl label nodes <node-name> node=openebs
Find apiServer, provisioner, snapshotOperator, admission-server and ndm sections in values.yamland update nodeSelector key. Example of the updated provisioner section in the following snippet where node:openebs is the nodeSelector label.
provisioner:
image: "quay.io/openebs/openebs-k8s-provisioner"
imageTag: "2.0.0"
replicas: 1
nodeSelector: {}
tolerations: []
affinity: {}
healthCheck:
initialDelaySeconds: 30
periodSeconds: 60
For disk filters in values.yaml (helm)
In thevalues.yaml, findndm section to update excludeVendors: and excludePaths:
ndm:
image: "quay.io/openebs/node-disk-manager-amd64"
imageTag: "0.8.0"
sparse:
path: "/var/openebs/sparse"
size: "10737418240"
count: "1"
filters:
excludeVendors: "CLOUDBYT,OpenEBS"
includePaths: ""
excludePaths: "loop,fd0,sr0,/dev/ram,/dev/dm-,/dev/md"
probes:
enableSeachest: false
nodeSelector: {}
healthCheck:
initialDelaySeconds: 30
periodSeconds: 60
Default Values for Helm Chart Parameters
Download the values.yaml from here and update them as per your needs.
Example configurations - kubectl
For nodeSelectors in openebs-operator.yaml
First, label the required nodes with an appropriate label. In the following command, the required nodes for storage nodes are labelled as node=openebs.kubectl label nodes <node-name> node=openebs
Next, in the downloaded openebs-operator.yaml, find the PodSpec for openebs-provisioner, maya-apiserver, openebs-snapshot-operator, openebs-admission-server and openebs-ndm pods and add the following key-value pair under nodeSelector field
nodeSelector:
node: openebs
For disk filters in openebs-operator.yaml
In the downloadedopenebs-operator.yaml, find openebs-ndm-config configmap and update the values for keys path-filter and vendor-filter
---
# This is the node-disk-manager related config.
# It can be used to customize the disks probes and filters
apiVersion: v1
kind: ConfigMap
metadata:
name: openebs-ndm-config
namespace: openebs
data:
# udev-probe is default or primary probe which should be enabled to run ndm
# filterconfigs contails configs of filters - in their form fo include
# and exclude comma separated strings
node-disk-manager.config: |
probeconfigs:
- key: udev-probe
name: udev probe
state: true
- key: seachest-probe
name: seachest probe
state: false
- key: smart-probe
name: smart probe
state: true
filterconfigs:
- key: os-disk-exclude-filter
name: os disk exclude filter
state: true
exclude: "/,/etc/hosts,/boot"
- key: vendor-filter
name: vendor filter
state: true
include: ""
exclude: "CLOUDBYT,OpenEBS"
- key: path-filter
name: path filter
state: true
include: ""
exclude: "loop,/dev/fd0,/dev/sr0,/dev/ram,/dev/dm-,/dev/md"
---
See Also:
OpenEBS Architecture
Installation troubleshooting
OpenEBS use cases
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