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BRIX On-Premises > BRIX On-Premises Enterprise > Install add-on components for BRIX / Install Descheduler

Install Descheduler

The Descheduler is used for redistributing workloads among the nodes of a Kubernetes cluster by evicting Pods. The Descheduler periodically checks the placement of Pods in the Kubernetes cluster and evicts them to less loaded nodes using a set of pre-configured strategies. For Descheduler to operate, a minimum of three nodes in the Kubernetes cluster is required.

начало внимание 

For a Kubernetes clusters deployed on the Deckhouse platform, the installation of Descheduler is not required. In this case, use the built-in module.

конец внимание 

The installation consists of three steps:

  1. Download the Helm chart and the configuration file.
  2. Fill out the configuration file.
  3. Install the Descheduler chart using helm in the Kubernetes cluster.

Step 1: Download the Helm chart and the configuration file

To install via the internet, obtain the configuration file values-descheduler.yaml by executing the command:

helm repo add elma365 https://charts.elma365.tech
helm repo update
helm show values elma365/descheduler > values-descheduler.yaml

Obtaining the configuration file for installation in a closed loop without internet access

  1. On a computer with internet access, download the BRIX images and upload them to your local image registry by executing the following command:

helm repo add elma365 https://charts.elma365.tech
helm repo update
helm pull elma365/descheduler

For more details, see Download BRIX images.

  1. Copy the downloaded chart archive descheduler-X.Y.Z.tgz onto the server where the installation will take place.
  1. Unpack this chart and copy the default configuration file values.yaml to values-descheduler.yaml:

tar -xf descheduler-X.Y.Z.tgz
cp descheduler/values.yaml values-descheduler.yaml

Step 2: Fill out the configuration file

Fill out the configuration file values-descheduler.yaml for the Descheduler installation.

For this purpose, configure the frequency of the Descheduler by setting the desired interval in minutes for the parameter descheduler.deschedulingInterval. The default interval is set to 2 minutes. The Descheduler is installed in namespace kube-system. This namespace is set by default.

# Descheduler settings (at least 3 nodes in the cluster are required)
descheduler:
  # override service name
  fullnameOverride: descheduler
  # run as a CronJob or Deployment
  kind: Deployment
  # namespace for descheduler (must be created before installation with kubectl create ns kube-system)
  namespace: kube-system
  # sets the time between consecutive executions of descheduler
  deschedulingInterval: 2m
  # selectors to run on specific nodes
  nodeSelector: {}
...

Filling in the connection parameters to the private registry for installation in a closed loop without internet access

 
To connect to a private registry, you need to:

  1. Download the BRIX images and upload them to your local image registry. Read more about this Download BRIX images.
  2. Set the address and path for the parameter image.repository.
  3. Indicate the name of the secret with access rights to the private registry in the parameter imagePullSecrets. The secret must be created manually and encrypted in Base64.

# Descheduler settings (at least 3 nodes in the cluster are required)
descheduler:
...
  # Connection parameters to the private registry
  image:
    # address and path for the private registry
    repository: registry.example.com/descheduler/descheduler
  # the secret with access rights to the private registry must be manually created, encrypted in Base64
  imagePullSecrets:
    - myRegistryKeySecretName

Where the repository format is as follows:

  • Addres is registry.example.com.
  • Path is /descheduler/descheduler.

Step 3: Install the Descheduler chart using helm in the Kubernetes cluster

Install the Descheduler chart in namespace kube-system.

For online installation:

helm upgrade --install descheduler elma365/descheduler -f values-descheduler.yaml -n kube-system 

For offline installation without internet access, navigate to the directory with the downloaded chart and execute the command:

helm upgrade --install descheduler ./descheduler -f values-descheduler.yaml -n kube-system

Delete the Descheduler chart using helm in the Kubernetes cluster

To delete the Descheduler chart in namespace kube-system, execute the command:

helm uninstall descheduler -n kube-system 

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