SessionStorage

Session storage utilizes Kask, a RESTful opaque key/value storage abstraction on top of Apache Cassandra.

Production Environment

Service endpoints

https://sessionstore.discovery.wmnet:8081/sessions/v1

eqiad

https://sessionstore.svc.eqiad.wmnet:8081/sessions/v1

codfw

https://sessionstore.svc.codfw.wmnet:8081/sessions/v1

staging

https://staging.svc.eqiad.wmnet:8081

Prometheus metrics

https://sessionstore.discovery.wmnet:8081/metrics

Readiness

https://sessionstore.discovery.wmnet:8081/healthz

Deployment

Deployment-prep

Unlike production, Docker is used to deploy the session storage service in the deployment-prep environment.

In a web browser:

1. Visit https://horizon.wikimedia.org
2. Select the deployment-prep project
3. Select Project → Instances (in the sidebar)
4. Locate and select the deployment-sessionstore02 instance
5. Select the Puppet Configuration tab
6. Scroll to the bottom of the page, and click edit for Hiera Config (see below)
7. Click "Apply Changes"
8. Run sudo puppet agent -tv from deployment-sessionstore02

Sample Hiera Config

profile::cassandra::instances:
  deployment-sessionstore02.deployment-prep.eqiad1.wikimedia.cloud: {}
profile::docker::engine::declare_service: true
profile::docker::engine::settings: {}
profile::docker::engine::version: 1.12.6-0~debian-jessie
profile::docker::runner::service_defs:
  mediawiki-services-kask:
    config:
      base_uri: /sessions/v1
      cassandra:
        authentication:
          password: cassandra
          username: cassandra
        hosts:
        - deployment-sessionstore02.deployment-prep.eqiad1.wikimedia.cloud
        keyspace: sessions
        table: values
      default_ttl: 86400
      listen_address: 0.0.0.0
      listen_port: 8080
      openapi_spec: /go/src/gerrit.wikimedia.org/r/mediawiki/services/kask/openapi.yaml
      service_name: sessions
    namespace: wikimedia
    override_cmd: ./kask --config /etc/mediawiki-services-kask/config.yaml
    port: 8080
    version: 2019-06-11-154352-production

k8s

See also: Migrating from scap-helm

Staging

cd /srv/deployment-charts/helmfile.d/services/staging/sessionstore
source .hfenv
helmfile diff
helmfile apply

Production

cd /srv/deployment-charts/helmfile.d/services/eqiad/sessionstore
source .hfenv
helmfile diff
helmfile apply

cd /srv/deployment-charts/helmfile.d/services/codfw/sessionstore
source .hfenv
helmfile diff
helmfile apply

Command cheetsheet

helmfile {status,diff,apply}
kubectl get pods <POD> -o yaml

# Tailing log files
kubectl logs -f --since 60m -c kask-staging <POD ID>

kubectl describe pod <POD> -n sessionstore
kubectl get events # Doesn't work, open phab request

# Port forward to the service running on <POD> (useful for testing)
kubectl -n sessionstore port-forward <POD> :8081

See also

• mw:Kask