add Linode cloud provider

cluster-autoscaler/README.md

@@ -21,6 +21,7 @@ You should also take a look at the notes and "gotchas" for your specific cloud p
 * [Packet](./cloudprovider/packet/README.md#notes) 
 * [IonosCloud](./cloudprovider/ionoscloud/README.md)
 * [OVHcloud](./cloudprovider/ovhcloud/README.md)
+* [Linode](./cloudprovider/linode/README.md)
 
 # Releases
 
@@ -151,3 +152,4 @@ Supported cloud providers:
 * Exoscale https://github.com/kubernetes/autoscaler/blob/master/cluster-autoscaler/cloudprovider/exoscale/README.md
 * Packet https://github.com/kubernetes/autoscaler/blob/master/cluster-autoscaler/cloudprovider/packet/README.md
 * OVHcloud https://github.com/kubernetes/autoscaler/blob/master/cluster-autoscaler/cloudprovider/ovhcloud/README.md
+* Linode https://github.com/kubernetes/autoscaler/blob/master/cluster-autoscaler/cloudprovider/linode/README.md

cluster-autoscaler/cloudprovider/builder/builder_all.go

@@ -1,4 +1,4 @@
-// +build !gce,!aws,!azure,!kubemark,!alicloud,!magnum,!digitalocean,!clusterapi,!huaweicloud,!ionoscloud
+// +build !gce,!aws,!azure,!kubemark,!alicloud,!magnum,!digitalocean,!clusterapi,!huaweicloud,!ionoscloud,!linode
 
 /*
 Copyright 2018 The Kubernetes Authors.
@@ -31,6 +31,7 @@ import (
 	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/gce"
 	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/huaweicloud"
 	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/ionoscloud"
+	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/linode"
 	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/magnum"
 	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/ovhcloud"
 	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/packet"
@@ -52,6 +53,7 @@ var AvailableCloudProviders = []string{
 	cloudprovider.OVHcloudProviderName,
 	clusterapi.ProviderName,
 	cloudprovider.IonoscloudProviderName,
+	cloudprovider.LinodeProviderName,
 }
 
 // DefaultCloudProvider is GCE.
@@ -87,6 +89,8 @@ func buildCloudProvider(opts config.AutoscalingOptions, do cloudprovider.NodeGro
 		return clusterapi.BuildClusterAPI(opts, do, rl)
 	case cloudprovider.IonoscloudProviderName:
 		return ionoscloud.BuildIonosCloud(opts, do, rl)
+	case cloudprovider.LinodeProviderName:
+		return linode.BuildLinode(opts, do, rl)
 	}
 	return nil
 }

cluster-autoscaler/cloudprovider/builder/builder_linode.go

@@ -0,0 +1,42 @@
+// +build linode
+
+/*
+Copyright 2018 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package builder
+
+import (
+	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider"
+	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/linode"
+	"k8s.io/autoscaler/cluster-autoscaler/config"
+)
+
+// AvailableCloudProviders supported by the cloud provider builder.
+var AvailableCloudProviders = []string{
+	cloudprovider.LinodeProviderName,
+}
+
+// DefaultCloudProvider for linode-only build is linode.
+const DefaultCloudProvider = cloudprovider.LinodeProviderName
+
+func buildCloudProvider(opts config.AutoscalingOptions, do cloudprovider.NodeGroupDiscoveryOptions, rl *cloudprovider.ResourceLimiter) cloudprovider.CloudProvider {
+	switch opts.CloudProviderName {
+	case cloudprovider.LinodeProviderName:
+		return linode.BuildLinode(opts, do, rl)
+	}
+
+	return nil
+}

cluster-autoscaler/cloudprovider/cloud_provider.go

@@ -53,6 +53,8 @@ const (
 	IonoscloudProviderName = "ionoscloud"
 	// OVHcloudProviderName gets the provider name of ovhcloud
 	OVHcloudProviderName = "ovhcloud"
+	// LinodeProviderName gets the provider name of linode
+	LinodeProviderName = "linode"
 )
 
 // CloudProvider contains configuration info and functions for interacting with

cluster-autoscaler/cloudprovider/linode/README.md

@@ -0,0 +1,62 @@
+# Cluster Autoscaler for Linode
+
+The cluster autoscaler for Linode scales nodes in a LKE cluster.
+
+## Linode Kubernetes Engine
+
+Linode Kubernetes Engine ([LKE](https://www.linode.com/docs/guides/deploy-and-manage-a-cluster-with-linode-kubernetes-engine-a-tutorial/)) is the managed K8s solution provided by Linode.
+
+LKE lets users create Node Pools, i.e. groups of nodes (also called Linodes) each of the same type.
+
+The size of a Node Pool can be configured at any moment. The user cannot select specific nodes to be deleted when downsizing a Node Pool, rather, Linode will randomly select nodes to be deleted to reach the defined size, even if a node is not healthy or has been manually deleted.
+
+Nodes in a Node Pool are considered disposable: they can be deleted and recreated at any moment, deleting a single node or using the *recycle* feature, on these cases the node will be recreated by Linode after a small amount of time.
+
+Node Pools do not support user defined tags or labels.
+
+There is no limitation on the number of Node Pool a LKE Cluster can have, limited to the maximum number of nodes an LKE Cluster can have.
+
+## Cluster Autoscaler
+
+A cluster autoscaler node group is composed of multiple LKE Node Pools of the same Linode type (e.g. g6-standard-1, g6-standard-2), each holding a *single* Linode.
+
+At every scan interval the cluster autoscaler reviews every LKE Node Pool and if:
+* it is not among the ones to be excluded as defined in the configuration file;
+* it holds a single Linode;
+
+then it becomes part of the node group holding LKE Node Pools of the Linode type it has, or a node group is created with this LKE Node Pool inside if there are no node groups with that Linode type at the moment.
+
+Scaling is achieved adding LKE Node Pools to node groups, *not* increasing the size of a LKE Node Pool, that must stay 1. The reason behind this is that Linode does not provide a way to selectively delete a Linode from a LKE Node Pool and decrease the size of the pool with it.
+
+This is also the reason we cannot use the standard `nodes` and `node-group-auto-discovery` cluster autoscaler flag (no labels could be used to select a specific node group), and the reason why there can be no node group of the same type.
+
+## Configuration
+
+The cluster autoscaler automatically select every LKE Node Pool that is part of a LKE cluster, so there is no need define the `node-group-auto-discovery` or `nodes` flags, see [examples/cluster-autoscaler-autodiscover.yaml](examples/cluster-autoscaler-autodiscover.yaml) for an example of a kubernetes deployment.
+
+It is mandatory to define the cloud configuration file `cloud-config`.
+You can see an example of the cloud config file at [examples/cluster-autoscaler-secret.yaml](examples/cluster-autoscaler-secret.yaml), it is an INI file with the following fields:
+
+| Key | Value | Mandatory | Default |
+|-----|-------|-----------|---------|
+| global/linode-token | Linode API Token with Read/Write permission for Kubernetes and Linodes | yes | none |
+| global/lke-cluster-id | ID of the LKE cluster (numeric of the form: 12345, you can get this via `linode-cli` or looking at the first number of a linode in a pool, e.g. for lke15989-19461-5fec9212fad2 the lke-cluster-id is "15989") | yes | none |
+| global/defaut-min-size-per-linode-type | minimum size of a node group (must be > 0) | no | 1 |
+| global/defaut-max-size-per-linode-type | maximum size of a node group | no | 254 |
+| global/do-not-import-pool-id | Pool id (numeric of the form: 12345) that will be excluded from the pools managed by the cluster autoscaler; can be repeated | no | none
+| nodegroup \"linode_type\"/min-size" | minimum size for a specific node group | no | global/defaut-min-size-per-linode-type |
+| nodegroup \"linode_type\"/max-size" | maximum size for a specific node group | no | global/defaut-min-size-per-linode-type |
+
+Log levels of intertest for the Linode provider are:
+* 1 (flag: ```--v=1```): basic logging at start;
+* 2 (flag: ```--v=2```): logging of the node group composition at every scan;
+
+## Development
+
+Make sure you are inside the `cluster-autoscaler` path of the [autoscaler repository](https://github.com/kubernetes/autoscaler).
+
+Create the docker image:
+```
+make container
+```
+tag the generated docker image and push it to a registry.

cluster-autoscaler/cloudprovider/linode/examples/cluster-autoscale-pdb.yaml

@@ -0,0 +1,9 @@
+apiVersion: policy/v1beta1
+kind: PodDisruptionBudget
+metadata:
+  name: cluster-autoscaler-pdb
+spec:
+  minAvailable: 1
+  selector:
+    matchLabels:
+      app: cluster-autoscaler

cluster-autoscaler/cloudprovider/linode/examples/cluster-autoscaler-autodiscover.yaml

@@ -0,0 +1,169 @@
+---
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  labels:
+    k8s-addon: cluster-autoscaler.addons.k8s.io
+    k8s-app: cluster-autoscaler
+  name: cluster-autoscaler
+  namespace: kube-system
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRole
+metadata:
+  name: cluster-autoscaler
+  labels:
+    k8s-addon: cluster-autoscaler.addons.k8s.io
+    k8s-app: cluster-autoscaler
+rules:
+  - apiGroups: [""]
+    resources: ["events", "endpoints"]
+    verbs: ["create", "patch"]
+  - apiGroups: [""]
+    resources: ["pods/eviction"]
+    verbs: ["create"]
+  - apiGroups: [""]
+    resources: ["pods/status"]
+    verbs: ["update"]
+  - apiGroups: [""]
+    resources: ["endpoints"]
+    resourceNames: ["cluster-autoscaler"]
+    verbs: ["get", "update"]
+  - apiGroups: [""]
+    resources: ["nodes"]
+    verbs: ["watch", "list", "get", "update"]
+  - apiGroups: [""]
+    resources:
+      - "pods"
+      - "services"
+      - "replicationcontrollers"
+      - "persistentvolumeclaims"
+      - "persistentvolumes"
+    verbs: ["watch", "list", "get"]
+  - apiGroups: ["extensions"]
+    resources: ["replicasets", "daemonsets"]
+    verbs: ["watch", "list", "get"]
+  - apiGroups: ["policy"]
+    resources: ["poddisruptionbudgets"]
+    verbs: ["watch", "list"]
+  - apiGroups: ["apps"]
+    resources: ["statefulsets", "replicasets", "daemonsets"]
+    verbs: ["watch", "list", "get"]
+  - apiGroups: ["storage.k8s.io"]
+    resources: ["storageclasses", "csinodes"]
+    verbs: ["watch", "list", "get"]
+  - apiGroups: ["batch", "extensions"]
+    resources: ["jobs"]
+    verbs: ["get", "list", "watch", "patch"]
+  - apiGroups: ["coordination.k8s.io"]
+    resources: ["leases"]
+    verbs: ["create"]
+  - apiGroups: ["coordination.k8s.io"]
+    resourceNames: ["cluster-autoscaler"]
+    resources: ["leases"]
+    verbs: ["get", "update"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: cluster-autoscaler
+  namespace: kube-system
+  labels:
+    k8s-addon: cluster-autoscaler.addons.k8s.io
+    k8s-app: cluster-autoscaler
+rules:
+  - apiGroups: [""]
+    resources: ["configmaps"]
+    verbs: ["create","list","watch"]
+  - apiGroups: [""]
+    resources: ["configmaps"]
+    resourceNames: ["cluster-autoscaler-status", "cluster-autoscaler-priority-expander"]
+    verbs: ["delete", "get", "update", "watch"]
+
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRoleBinding
+metadata:
+  name: cluster-autoscaler
+  labels:
+    k8s-addon: cluster-autoscaler.addons.k8s.io
+    k8s-app: cluster-autoscaler
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: cluster-autoscaler
+subjects:
+  - kind: ServiceAccount
+    name: cluster-autoscaler
+    namespace: kube-system
+
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: cluster-autoscaler
+  namespace: kube-system
+  labels:
+    k8s-addon: cluster-autoscaler.addons.k8s.io
+    k8s-app: cluster-autoscaler
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: cluster-autoscaler
+subjects:
+  - kind: ServiceAccount
+    name: cluster-autoscaler
+    namespace: kube-system
+
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: cluster-autoscaler
+  namespace: kube-system
+  labels:
+    app: cluster-autoscaler
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: cluster-autoscaler
+  template:
+    metadata:
+      labels:
+        app: cluster-autoscaler
+      annotations:
+        prometheus.io/scrape: 'true'
+        prometheus.io/port: '8085'
+    spec:
+      serviceAccountName: cluster-autoscaler
+      containers:
+        - image: k8s.gcr.io/autoscaling/cluster-autoscaler:latest
+          name: cluster-autoscaler
+          resources:
+            limits:
+              cpu: 100m
+              memory: 300Mi
+            requests:
+              cpu: 100m
+              memory: 300Mi
+          command:
+            - ./cluster-autoscaler
+            - --v=2
+            - --cloud-provider=linode
+            - --cloud-config=/config/cloud-config
+          volumeMounts:
+            - name: ssl-certs
+              mountPath: /etc/ssl/certs/ca-certificates.crt
+              readOnly: true
+            - name: cloud-config
+              mountPath: /config
+              readOnly: true
+          imagePullPolicy: "Always"
+      volumes:
+        - name: ssl-certs
+          hostPath:
+            path: "/etc/ssl/certs/ca-certificates.crt"
+        - name: cloud-config
+          secret:
+            secretName: cluster-autoscaler-cloud-config

cluster-autoscaler/cloudprovider/linode/examples/cluster-autoscaler-secret.yaml

@@ -0,0 +1,26 @@
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: cluster-autoscaler-cloud-config
+  namespace: kube-system
+type: Opaque
+stringData:
+  cloud-config: |-
+    [global]
+    linode-token=55b4c52123462dk23sa165cc3dba1234123125666f1422c8
+    lke-cluster-id=12345
+    defaut-min-size-per-linode-type=1
+    defaut-max-size-per-linode-type=10
+    do-not-import-pool-id=19462
+    do-not-import-pool-id=19763
+
+    [nodegroup "g6-standard-1"]
+    min-size=2
+    max-size=5
+
+    [nodegroup "g6-standard-2"]
+    max-size=4
+
+    [nodegroup "g6-standard-4"]
+    max-size=2