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Microsoft Azure Container Service Engine - Cluster Definition

Cluster Defintions for apiVersion "vlabs"

Here are the cluster definitions for apiVersion "vlabs"

apiVersion

Name Required Description
apiVersion yes The version of the template. For "vlabs" the value is "vlabs".

orchestratorProfile

orchestratorProfile describes the orchestrator settings.

Name Required Description
orchestratorType yes This specifies the orchestrator type for the cluster.

Here are the valid values for the orchestrator types:

  1. DCOS - this represents the DC/OS orchestrator. Older releases of DCOS 1.8 may be specified.
  2. Kubernetes - this represents the Kubernetes orchestrator.
  3. Swarm - this represents the Swarm orchestrator.
  4. Swarm Mode - this represents the Swarm Mode orchestrator.

kubernetesConfig

kubernetesConfig describes Kubernetes specific configuration.

Name Required Description
kubernetesImageBase no This specifies the base URL (everything preceding the actual image filename) of the kubernetes hyperkube image to use for cluster deployment, e.g., k8s-gcrio.azureedge.net/.
dockerEngineVersion no Which version of docker-engine to use in your cluster, e.g.. "17.03.*"
networkPolicy no Specifies the network policy tool for the cluster. Valid values are:
"azure" (default), which provides an Azure native networking experience,
none for not enforcing any network policy,
calico for Calico network policy (required for Kubernetes network policies; clusters with Linux agents only).
See network policy examples for more information.
containerRuntime no The container runtime to use as a backend. The default is docker. The only other option is clear-containers.
clusterSubnet no The IP subnet used for allocating IP addresses for pod network interfaces. The subnet must be in the VNET address space. Default value is 10.244.0.0/16.
dnsServiceIP no IP address for kube-dns to listen on. If specified must be in the range of serviceCidr.
dockerBridgeSubnet no The specific IP and subnet used for allocating IP addresses for the docker bridge network created on the kubernetes master and agents. Default value is 172.17.0.1/16. This value is used to configure the docker daemon using the --bip flag.
serviceCidr no IP range for Service IPs, Default is "10.0.0.0/16". This range is never routed outside of a node so does not need to lie within clusterSubnet or the VNet.
enableRbac no Enable Kubernetes RBAC (boolean - default == true)
enableAggregatedAPIs no Enable Kubernetes Aggregated APIs.This is required by Service Catalog. (boolean - default == false)
enableDataEncryptionAtRest no Enable kuberetes data encryption at rest.This is currently an alpha feature. (boolean - default == false)
enablePrivateCluster no Build a cluster without public addresses assigned (boolean - default == false)
maxPods no The maximum number of pods per node. The minimum valid value, necessary for running kube-system pods, is 5. Default value is 30 when networkPolicy equals azure, 110 otherwise.
gcHighThreshold no Sets the --image-gc-high-threshold value on the kublet configuration. Default is 85. See kubelet Garbage Collection
gcLowThreshold no Sets the --image-gc-low-threshold value on the kublet configuration. Default is 80. See kubelet Garbage Collection
useInstanceMetadata no Use the Azure cloudprovider instance metadata service for appropriate resource discovery operations. Default is true.
addons no Configure various Kubernetes addons configuration (currently supported: tiller, kubernetes-dashboard). See addons configuration below.
kubeletConfig no Configure various runtime configuration for kubelet. See kubeletConfig below.
controllerManagerConfig no Configure various runtime configuration for controller-manager. See controllerManagerConfig below.
cloudControllerManagerConfig no Configure various runtime configuration for cloud-controller-manager. See cloudControllerManagerConfig below.
apiServerConfig no Configure various runtime configuration for apiserver. See apiServerConfig below.

addons

addons describes various addons configuration. It is a child property of kubernetesConfig. Below is a list of currently available addons:

Name of addon Enabled by default? How many containers Description
tiller true 1 Delivers the Helm server-side component: tiller. See https://github.com/kubernetes/helm for more info.
kubernetes-dashboard true 1 Delivers the kubernetes dashboard component. See https://github.com/kubernetes/dashboard for more info.
rescheduler false 1 Delivers the kubernetes rescheduler component.

To give a bit more info on the addons property: We've tried to expose the basic bits of data that allow useful configuration of these cluster features. Here are some example usage patterns that will unpack what addons provide:

To enable an addon (using "tiller" as an example):

"kubernetesConfig": {
    "addons": [
        {
            "name": "tiller",
            "enabled" : true
        }
    ]
}

As you can see above, addons is an array child property of kubernetesConfig. Each addon that you want to add custom configuration to would be represented as an object item in the array. For example, to disable both tiller and dashboard:

"kubernetesConfig": {
    "addons": [
        {
            "name": "tiller",
            "enabled" : false
        },
        {
            "name": "kubernetes-dashboard",
            "enabled" : false
        }
    ]
}

More usefully, let's add some custom configuration to both of the above addons:

"kubernetesConfig": {
    "addons": [
        {
            "name": "tiller",
            "containers": [
                {
                  "name": "tiller",
                  "image": "myDockerHubUser/tiller:v3.0.0-alpha",
                  "cpuRequests": "1",
                  "memoryRequests": "1024Mi",
                  "cpuLimits": "1",
                  "memoryLimits": "1024Mi"
                }
              ]
        },
        {
            "name": "kubernetes-dashboard",
            "containers": [
                {
                  "name": "kubernetes-dashboard",
                  "cpuRequests": "50m",
                  "memoryRequests": "512Mi",
                  "cpuLimits": "50m",
                  "memoryLimits": "512Mi"
                }
              ]
        }
    ]
}

Above you see custom configuration for both tiller and kubernetes-dashboard. Both include specific resource limit values across the following dimensions:

  • cpuRequests
  • memoryRequests
  • cpuLimits
  • memoryLimits

See https://kubernetes.io/docs/concepts/configuration/manage-compute-resources-container/ for more on Kubernetes resource limits.

Additionally above, we specified a custom docker image for tiller, let's say we want to build a cluster and test an alpha version of tiller in it.

Finally, the addons.enabled boolean property was omitted above; that's by design. If you specify a containers configuration, acs-engine assumes you're enabling the addon. The very first example above demonstrates a simple "enable this addon with default configuration" declaration.

kubeletConfig

kubeletConfig declares runtime configuration for the kubelet running on all master and agent nodes. It is a generic key/value object, and a child property of kubernetesConfig. An example custom kubelet config:

"kubernetesConfig": {
    "kubeletConfig": {
        "--eviction-hard": "memory.available<250Mi,nodefs.available<20%,nodefs.inodesFree<10%"
    }
}

See here for a reference of supported kubelet options.

Below is a list of kubelet options that acs-engine will configure by default:

kubelet option default value
"--cloud-config" "/etc/kubernetes/azure.json"
"--cloud-provider" "azure"
"--cluster-domain" "cluster.local"
"--pod-infra-container-image" "pause-amd64:"
"--max-pods" "110"
"--eviction-hard" "memory.available<100Mi,nodefs.available<10%,nodefs.inodesFree<5%"
"--node-status-update-frequency" "10s"
"--image-gc-high-threshold" "85"
"--image-gc-low-threshold" "850"
"--non-masquerade-cidr" "10.0.0.0/8"
"--feature-gates" No default (can be a comma-separated list). On agent nodes Accelerators=true will be applied in the --feature-gates option.

Below is a list of kubelet options that are not currently user-configurable, either because a higher order configuration vector is available that enforces kubelet configuration, or because a static configuration is required to build a functional cluster:

kubelet option default value
"--address" "0.0.0.0"
"--azure-container-registry-config" "/etc/kubernetes/azure.json"
"--allow-privileged" "true"
"--pod-manifest-path" "/etc/kubernetes/manifests"
"--network-plugin" "cni"
"--node-labels" (based on Azure node metadata)
"--cgroups-per-qos" "true"
"--enforce-node-allocatable" "pods"
"--kubeconfig" "/var/lib/kubelet/kubeconfig"
"--register-node" (master nodes only) "true"
"--register-with-taints" (master nodes only) "node-role.kubernetes.io/master=true:NoSchedule"
"--keep-terminated-pod-volumes" "false"

controllerManagerConfig

controllerManagerConfig declares runtime configuration for the kube-controller-manager daemon running on all master nodes. Like kubeletConfig it is a generic key/value object, and a child property of kubernetesConfig. An example custom controller-manager config:

"kubernetesConfig": {
    "controllerManagerConfig": {
        "--node-monitor-grace-period": "40s",
        "--pod-eviction-timeout": "5m0s",
        "--route-reconciliation-period": "10s"
        "--terminated-pod-gc-threshold": "5000"
    }
}

See here for a reference of supported controller-manager options.

Below is a list of controller-manager options that acs-engine will configure by default:

controller-manager option default value
"--node-monitor-grace-period" "40s"
"--pod-eviction-timeout" "5m0s"
"--route-reconciliation-period" "10s"
"--terminated-pod-gc-threshold" "5000"
"--feature-gates" No default (can be a comma-separated list)

Below is a list of controller-manager options that are not currently user-configurable, either because a higher order configuration vector is available that enforces controller-manager configuration, or because a static configuration is required to build a functional cluster:

controller-manager option default value
"--kubeconfig" "/var/lib/kubelet/kubeconfig"
"--allocate-node-cidrs" "false"
"--cluster-cidr" "10.240.0.0/12"
"--cluster-name"
"--cloud-provider" "azure"
"--cloud-config" "/etc/kubernetes/azure.json"
"--root-ca-file" "/etc/kubernetes/certs/ca.crt"
"--cluster-signing-cert-file" "/etc/kubernetes/certs/ca.crt"
"--cluster-signing-key-file" "/etc/kubernetes/certs/ca.key"
"--service-account-private-key-file" "/etc/kubernetes/certs/apiserver.key"
"--leader-elect" "true"
"--v" "2"
"--profiling" "false"
"--use-service-account-credentials" "false" ("true" if kubernetesConfig.enableRbac is true)

cloudControllerManagerConfig

cloudControllerManagerConfig declares runtime configuration for the cloud-controller-manager daemon running on all master nodes in a Cloud Controller Manager configuration. Like kubeletConfig it is a generic key/value object, and a child property of kubernetesConfig. An example custom cloud-controller-manager config:

"kubernetesConfig": {
    "cloudControllerManagerConfig": {
        "--route-reconciliation-period": "1m"
    }
}

See here for a reference of supported controller-manager options.

Below is a list of cloud-controller-manager options that acs-engine will configure by default:

controller-manager option default value
"--route-reconciliation-period" "10s"

Below is a list of cloud-controller-manager options that are not currently user-configurable, either because a higher order configuration vector is available that enforces controller-manager configuration, or because a static configuration is required to build a functional cluster:

controller-manager option default value
"--kubeconfig" "/var/lib/kubelet/kubeconfig"
"--allocate-node-cidrs" "false"
"--cluster-cidr" "10.240.0.0/12"
"--cluster-name"
"--cloud-provider" "azure"
"--cloud-config" "/etc/kubernetes/azure.json"
"--leader-elect" "true"
"--v" "2"

apiServerConfig

apiServerConfig declares runtime configuration for the kube-apiserver daemon running on all master nodes. Like kubeletConfig and controllerManagerConfig it is a generic key/value object, and a child property of kubernetesConfig. An example custom apiserver config:

"kubernetesConfig": {
    "apiServerConfig": {
        "--request-timeout": "30s"
    }
}

Or perhaps you want to customize/override the set of admission-control flags passed to the API Server by default, you can omit the options you don't want and specify only the ones you need as follows:

"orchestratorProfile": {
      "orchestratorType": "Kubernetes",
      "orchestratorRelease": "1.8",
      "kubernetesConfig": {
        "apiServerConfig": {
          "--admission-control":  "NamespaceLifecycle,LimitRanger,ServiceAccount,DefaultStorageClass,ResourceQuota,AlwaysPullImages"
        }
      }
    }

See here for a reference of supported apiserver options.

Below is a list of apiserver options that acs-engine will configure by default:

apiserver option default value
"--admission-control" "NamespaceLifecycle, LimitRanger, ServiceAccount, DefaultStorageClass, ResourceQuota, DenyEscalatingExec, AlwaysPullImages, SecurityContextDeny"
"--authorization-mode" "Node", "RBAC" (the latter if enabledRbac is true)
"--audit-log-maxage" "30"
"--audit-log-maxbackup" "10"
"--audit-log-maxsize" "100"
"--feature-gates" No default (can be a comma-separated list)

Below is a list of apiserver options that are not currently user-configurable, either because a higher order configuration vector is available that enforces kubelet configuration, or because a static configuration is required to build a functional cluster:

apiserver option default value
"--bind-address" "0.0.0.0"
"--advertise-address" calculated value that represents listening URI for API server
"--allow-privileged" "true"
"--anonymous-auth" "false
"--audit-log-path" "/var/log/apiserver/audit.log"
"--insecure-port" "8080"
"--secure-port" "443"
"--service-account-lookup" "true"
"--etcd-cafile" "/etc/kubernetes/certs/ca.crt"
"--etcd-certfile" "/etc/kubernetes/certs/etcdclient.crt"
"--etcd-keyfile" "/etc/kubernetes/certs/etcdclient.key"
"--etcd-servers" calculated value that represents etcd servers
"--etcd-quorum-read" "true"
"--profiling" "false"
"--repair-malformed-updates" "false"
"--tls-cert-file" "/etc/kubernetes/certs/apiserver.crt"
"--tls-private-key-file" "/etc/kubernetes/certs/apiserver.key"
"--client-ca-file" "/etc/kubernetes/certs/ca.crt"
"--service-account-key-file" "/etc/kubernetes/certs/apiserver.key"
"--kubelet-client-certificate" "/etc/kubernetes/certs/client.crt"
"--kubelet-client-key" "/etc/kubernetes/certs/client.key"
"--service-cluster-ip-range" see serviceCIDR
"--storage-backend" calculated value that represents etcd version
"--v" "4"
"--experimental-encryption-provider-config" "/etc/kubernetes/encryption-config.yaml" (if enableDataEncryptionAtRest is true)
"--requestheader-client-ca-file" "/etc/kubernetes/certs/proxy-ca.crt" (if enableAggregatedAPIs is true)
"--proxy-client-cert-file" "/etc/kubernetes/certs/proxy.crt" (if enableAggregatedAPIs is true)
"--proxy-client-key-file" "/etc/kubernetes/certs/proxy.key" (if enableAggregatedAPIs is true)
"--requestheader-allowed-names" "" (if enableAggregatedAPIs is true)
"--requestheader-extra-headers-prefix" "X-Remote-Extra-" (if enableAggregatedAPIs is true)
"--requestheader-group-headers" "X-Remote-Group" (if enableAggregatedAPIs is true)
"--requestheader-username-headers" "X-Remote-User" (if enableAggregatedAPIs is true)
"--cloud-provider" "azure" (unless useCloudControllerManager is true)
"--cloud-config" "/etc/kubernetes/azure.json" (unless useCloudControllerManager is true)
"--oidc-username-claim" "oid" (if has AADProfile)
"--oidc-groups-claim" "groups" (if has AADProfile)
"--oidc-client-id" calculated value that represents OID client ID (if has AADProfile)
"--oidc-issuer-url" calculated value that represents OID issuer URL (if has AADProfile)

We consider kubeletConfig, controllerManagerConfig, and apiServerConfig to be generic conveniences that add power/flexibility to cluster deployments. Their usage comes with no operational guarantees! They are manual tuning features that enable low-level configuration of a kubernetes cluster.

masterProfile

masterProfile describes the settings for master configuration.

Name Required Description
count yes Masters have count value of 1, 3, or 5 masters
dnsPrefix yes this is the dns prefix for the masters FQDN. The master FQDN is used for SSH or commandline access. This must be a unique name. (bring your own VNET examples)
firstConsecutiveStaticIP only required when vnetSubnetId specified this is the IP address of the first master. IP Addresses will be assigned consecutively to additional master nodes.
vmsize yes Describes a valid Azure VM Sizes. These are restricted machines with at least 2 cores and 100GB of ephemeral disk space.
osDiskSizeGB no Describes the OS Disk Size in GB
vnetSubnetId no specifies the Id of an alternate VNET subnet. The subnet id must specify a valid VNET ID owned by the same subscription. (bring your own VNET examples)
extensions no This is an array of extensions. This indicates that the extension be run on a single master. The name in the extensions array must exactly match the extension name in the extensionProfiles.
vnetCidr no specifies the vnet cidr when using custom Vnets (bring your own VNET examples)
distro no Select Master(s) Operating System (Linux). Currently supported values are: ubuntu and coreos (CoreOS support is currently experimental). Defaults to ubuntu if undefined. Currently supported OS and orchestrator configurations -- ubuntu: DCOS, Docker Swarm, Kubernetes; coreos: Kubernetes. Example of CoreOS Master with CoreOS Agents

agentPoolProfiles

A cluster can have 0 to 12 agent pool profiles. Agent Pool Profiles are used for creating agents with different capabilities such as VMSizes, VMSS or Availability Set, Public/Private access, attached storage disks, attached managed disks, or Windows.

Name Required Description
availabilityProfile no, defaults to VirtualMachineScaleSets You can choose between VirtualMachineScaleSets and AvailabilitySet. As a rule of thumb always choose VirtualMachineScaleSets unless you need features such as dynamic attached disks or require Kubernetes
count yes Describes the node count
diskSizesGB no describes an array of up to 4 attached disk sizes. Valid disk size values are between 1 and 1024.
dnsPrefix required if agents are to be exposed publically with a load balancer this is the dns prefix that forms the FQDN to access the loadbalancer for this agent pool. This must be a unique name among all agent pools.
name yes This is the unique name for the agent pool profile. The resources of the agent pool profile are derived from this name.
ports only required if needed for exposing services publically Describes an array of ports need for exposing publically. A tcp probe is configured for each port and only opens to an agent node if the agent node is listening on that port. A maximum of 150 ports may be specified.
storageProfile no, defaults to StorageAccount specifies the storage profile to use. Valid values are StorageAccount or ManagedDisks
vmsize yes Describes a valid Azure VM Sizes. These are restricted to machines with at least 2 cores
osDiskSizeGB no Describes the OS Disk Size in GB
vnetSubnetId no specifies the Id of an alternate VNET subnet. The subnet id must specify a valid VNET ID owned by the same subscription. (bring your own VNET examples)
distro no Select Agent Pool(s) Operating System (Linux). Currently supported values are: ubuntu and coreos (CoreOS support is currently experimental). Defaults to ubuntu if undefined, unless osType is defined as Windows (in which case distro is unused). Currently supported OS and orchestrator configurations -- ubuntu: DCOS, Docker Swarm, Kubernetes; coreos: Kubernetes. Example of CoreOS Master with Windows and Linux (CoreOS and Ubuntu) Agents

linuxProfile

linuxProfile provides the linux configuration for each linux node in the cluster

Name Required Description
adminUsername yes describes the username to be used on all linux clusters
ssh.publicKeys.keyData yes The public SSH key used for authenticating access to all Linux nodes in the cluster. Here are instructions for generating a public/private key pair.
secrets no specifies an array of key vaults to pull secrets from and what secrets to pull from each

secrets

secrets details which certificates to install on the masters and nodes in the cluster.

A cluster can have a list of key vaults to install certs from.

On linux boxes the certs are saved on under the directory "/var/lib/waagent/". 2 files are saved per certificate:

  1. {thumbprint}.crt : this is the full cert chain saved in PEM format
  2. {thumbprint}.prv : this is the private key saved in PEM format
Name Required Description
sourceVault.id yes the azure resource manager id of the key vault to pull secrets from
vaultCertificates.certificateUrl yes key vault url to this cert including the version
format for sourceVault.id, can be obtained in cli, or found in the portal: /subscriptions/{subscription-id}/resourceGroups/{resource-group}/providers/Microsoft.KeyVault/vaults/{keyvaultname}

format for vaultCertificates.certificateUrl, can be obtained in cli, or found in the portal: https://{keyvaultname}.vault.azure.net:443/secrets/{secretName}/{version}

servicePrincipalProfile

servicePrincipalProfile describes an Azure Service credentials to be used by the cluster for self-configuration. See service principal for more details on creation.

Name Required Description
clientId yes, for Kubernetes clusters describes the Azure client id. It is recommended to use a separate client ID per cluster
secret yes, for Kubernetes clusters describes the Azure client secret. It is recommended to use a separate client secret per client id

Cluster Defintions for apiVersion "2016-03-30"

Here are the cluster definitions for apiVersion "2016-03-30". This matches the api version of the Azure Container Service Engine.

apiVersion

Name Required Description
apiVersion yes The version of the template. For "2016-03-30" the value is "2016-03-30".

orchestratorProfile

orchestratorProfile describes the orchestrator settings.

Name Required Description
orchestratorType yes This specifies the orchestrator type for the cluster.

Here are the valid values for the orchestrator types:

  1. DCOS - this represents the DC/OS orchestrator.
  2. Swarm - this represents the Swarm orchestrator.
  3. Kubernetes - this represents the Kubernetes orchestrator.
  4. Swarm Mode - this represents the Swarm Mode orchestrator.

masterProfile

masterProfile describes the settings for master configuration.

Name Required Description
count yes Masters have count value of 1, 3, or 5 masters
dnsPrefix yes this is the dns prefix for the masters FQDN. The master FQDN is used for SSH or commandline access. This must be a unique name. (bring your own VNET examples)

agentPoolProfiles

For apiVersion "2016-03-30", a cluster may have only 1 agent pool profiles.

Name Required Description
count yes Describes the node count
dnsPrefix required if agents are to be exposed publically with a load balancer this is the dns prefix that forms the FQDN to access the loadbalancer for this agent pool. This must be a unique name among all agent pools.
name yes This is the unique name for the agent pool profile. The resources of the agent pool profile are derived from this name.
vmsize yes Describes a valid Azure VM Sizes. These are restricted to machines with at least 2 cores

linuxProfile

linuxProfile provides the linux configuration for each linux node in the cluster

Name Required Description
adminUsername yes describes the username to be used on all linux clusters
ssh.publicKeys[0].keyData yes The public SSH key used for authenticating access to all Linux nodes in the cluster. Here are instructions for generating a public/private key pair.

aadProfile

linuxProfile provides AAD integration configuration for the cluster, currently only available for Kubernetes orchestrator.

Name Required Description
clientAppID yes describes the client AAD application ID
serverAppID yes describes the server AAD application ID
tenantID no describes the AAD tenant ID to use for authentication. If not specified, will use the tenant of the deployment subscription.

extensionProfiles

A cluster can have 0 - N extensions in extension profiles. Extension profiles allow a user to easily add pre-packaged functionality into a cluster. An example would be configuring a monitoring solution on your cluster. You can think of extensions like a marketplace for acs clusters.

Name Required Description
name yes the name of the extension. This has to exactly match the name of a folder under the extensions folder
version yes the version of the extension. This has to exactly match the name of the folder under the extension name folder
extensionParameters optional extension parameters may be required by extensions. The format of the parameters is also extension dependant.
rootURL optional url to the root location of extensions. The rootURL must have an extensions child folder that follows the extensions convention. The rootURL is mainly used for testing purposes.

You can find more information, as well as a list of extensions on the extensions documentation.