chore(jsonnet): Add backend component to loki-simple-scalable jsonnet (…

…#13976)

production/ksonnet/loki-simple-scalable/backend.libsonnet

@@ -0,0 +1,57 @@
+local k = import 'ksonnet-util/kausal.libsonnet';
+
+{
+  local container = k.core.v1.container,
+  local pvc = k.core.v1.persistentVolumeClaim,
+  local statefulSet = k.apps.v1.statefulSet,
+  local volumeMount = k.core.v1.volumeMount,
+  local service = k.core.v1.service,
+
+  _config+:: {
+    backend_replicas: 1,
+  },
+
+  // The backends
+  backend_pvc::
+    pvc.new('backend-data') +
+    pvc.mixin.spec.resources.withRequests({ storage: '10Gi' }) +
+    pvc.mixin.spec.withAccessModes(['ReadWriteOnce']) +
+    pvc.mixin.spec.withStorageClassName('fast'),
+
+  backend_args::
+    $._config.commonArgs {
+      target: 'backend',
+    },
+
+  backend_container::
+    container.new('backend', $._images.loki) +
+    container.withPorts($.util.defaultPorts) +
+    container.withArgsMixin(k.util.mapToFlags($.backend_args)) +
+    container.withVolumeMountsMixin([volumeMount.new('backend-data', '/data')]) +
+    container.mixin.readinessProbe.httpGet.withPath('/ready') +
+    container.mixin.readinessProbe.httpGet.withPort($._config.http_listen_port) +
+    container.mixin.readinessProbe.withInitialDelaySeconds(15) +
+    container.mixin.readinessProbe.withTimeoutSeconds(1),
+
+  backend_statefulset:
+    statefulSet.new('backend', $._config.backend_replicas, [$.backend_container], $.backend_pvc) +
+    statefulSet.mixin.spec.withServiceName('backend') +
+    statefulSet.mixin.metadata.withLabels({ app: $._config.headless_service_name, name: 'backend' }) +
+    statefulSet.mixin.spec.selector.withMatchLabels({ name: 'backend' }) +
+    statefulSet.mixin.spec.template.metadata.withLabels({ name: 'backend', app: $._config.headless_service_name }) +
+    $._config.config_hash_mixin +
+    k.util.configVolumeMount('loki', '/etc/loki') +
+    k.util.antiAffinity +
+    statefulSet.mixin.spec.updateStrategy.withType('RollingUpdate') +
+    statefulSet.mixin.spec.template.spec.securityContext.withFsGroup(10001) +  // 10001 is the group ID assigned to Loki in the Dockerfile
+    statefulSet.mixin.spec.template.spec.withTerminationGracePeriodSeconds(4800) +
+    statefulSet.mixin.spec.withPodManagementPolicy('Parallel'),
+
+  backend_service:
+    k.util.serviceFor($.backend_statefulset) +
+    service.mixin.spec.withType('ClusterIP') +
+    service.mixin.spec.withPorts([
+      k.core.v1.servicePort.newNamed('backend-http-metrics', 80, 'http-metrics'),
+      k.core.v1.servicePort.newNamed('backend-grpc', 9095, 'grpc'),
+    ]),
+}

production/ksonnet/loki-simple-scalable/loki.libsonnet

@@ -5,4 +5,5 @@
 // Loki services
 (import 'read.libsonnet') +
 (import 'write.libsonnet') +
+(import 'backend.libsonnet') +
 (import 'headless.libsonnet')