Advanced Topics

Advanced topic and settings for KubeCF: Ingress, Diego and Eirini, …

Diego vs Eirini

Diego is the standard scheduler used by KubeCF to deploy CF applications. Eirini is an alternative to Diego that follows a more Kubernetes native approach, deploying the CF apps directly to a Kubernetes namespace.

To activate this alternative, use the option: --set features.eirini.enabled=true when deploying kubecf from its chart.

Eirini is only supported with sle15 stacks for now. Hence, set them as so in your values yaml:

install_stacks: [sle15]

Diego Cell Affinities & Tainted Nodes

Note that the diego-cell pods used by the Diego standard scheduler are

  • privileged,
  • use large local emptyDir volumes (i.e. require node disk storage),
  • and set kernel parameters on the node.

These things all mean that these pods should not live next to other Kubernetes workloads. They should all be placed on their own dedicated nodes instead where possible.

This can be done by setting affinities and tolerations, as explained in the associated tutorial.

Ingress

By default, the cluster is exposed through its Kubernetes services.

To use the NGINX ingress instead, it is necessary to:

  • Install and configure the NGINX Ingress Controller.
  • Configure Kubecf to use the ingress controller.

This has to happen before deploying kubecf.

Installation of the NGINX Ingress Controller
helm install stable/nginx-ingress \
  --name ingress \
  --namespace ingress \
  --set "tcp.2222=kubecf/scheduler:2222" \
  --set "tcp.<services.tcp-router.port_range.start>=kubecf/tcp-router:<services.tcp-router.port_range.start>" \
  ...
  --set "tcp.<services.tcp-router.port_range.end>=kubecf/tcp-router:<services.tcp-router.port_range.end>"

The tcp.<port> option uses the NGINX TCP pass-through.

In the case of the tcp-router ports, one --set for each port is required, starting with services.tcp-router.port_range.start and ending with services.tcp-router.port_range.end. Those values are defined on the values.yaml file with default values.

Configure kubecf

Use the Helm option --set features.ingress.enabled=true when deploying kubecf.

External Database

By default, KubeCF includes an internal single-availability database. KubeCF also exposes a way to use an external database via the Helm property features.external_database. Check the values.yaml for more details.

Setting features.external_database.seed to true will allow KubeCF to configure the various required databases for you; however, this will require providing the root database password (via the var-pxc-root-password secret), which may be an issue under some policies.

It is also possible to manually create all necessary databases externally, and then provide the individual credentials to KubeCF. When deploying KubeCF with Helm, it will error out if any of the required database credentials are missing. An example configuration is below:

features:
  external_database:
    enabled: true
    type: mysql
    host: mariadb-server.corp.example.com
    port: 3306
    seed: false
    databases:
      uaa:
        name: uaa
        username: uaa-database-user
        password: PAWjxQst5l16J3w3vJdfX7fXY8HyHtyb
      cc:
        name: cloud_controller
        username: cc-database-user
        password: qj5KI3qwVe+XVFENAuEU9AfSkpUK/nzb
      bbs:
        name: diego
        username: diego-database-user
        password: z7gvkjWNUgX+xcn3Ia0loMEnAD7MXBgE
      routing_api:
        name: routing-api
        username: routing-api-database-user
        password: bTL6DhK89F+G05OZtHbvEdR1uwkyRMJt
      policy_server:
        name: network_policy
        username: network-policy-database-user
        password: EYviLFS/F4dAyVry5Stm8wrpOI64Xmnz
      silk_controller:
        name: network_connectivity
        username: silk-database-user
        password: ah7nbU1wsHuZ4BtmcdU1vV37KgVV2lLf
      locket:
        name: locket
        username: locket-database-user
        password: rWicBxhg8mIrhkuSR/aDlqljOMORuyL
      credhub:
        name: credhub
        username: credhub-database-user
        password: 5tJcIWHCR1QTLdfQDiN1Mz8K8jB+clD
      autoscaler:
        name: autoscaler
        username: autoscaler-database-user
        password: cYo2Tdi61N39mUjoEksXHuu3F7Dk58F
Last modified October 19, 2020: Update advanced-topics.md (5dd590b)