Master and Node Configuration | Installation and Configuration | OpenShift enterprise 3.2

Overview

The openshift start command is used to launch OpenShift enterprise servers. The command and its subcommands (master to launch a master server and node to launch a node server) all take a limited set of arguments that are sufficient for launching servers in a development or experimental environment.

However, these arguments are insufficient to describe and control the full set of configuration and security options that are necessary in a production environment. To provide those options, it is necessary to use the dedicated master and node configuration files.

Master configuration files and node configuration files are fully specified with no default values. Therefore, any empty value indicates that you want to start up with an empty value for that parameter. This makes it easy to reason about exactly what your configuration is, but it also makes it difficult to remember all of the options to specify. To make this easier, the configuration files can be created with the --write-config option and then used with the --config option.

Master Configuration Files

This section reviews parameters mentioned in the master-config.yaml file.

You can create a new master configuration file to see the valid options for your installed version of OpenShift enterprise.

Admission Control Configuration

Table 1. Admission Control Configuration Parameters
Parameter Name	Description
`AdmissionConfig`	Contains admission control plug-in configuration.
`APIServerArguments`	Key-value pairs that will be passed directly to the Kube API server that match the API servers' command line arguments. These are not migrated, but if you reference a value that does not exist the server will not start. These values may override other settings in `KubernetesMasterConfig`, which may cause invalid configurations.
`ControllerArguments`	Key-value pairs that will be passed directly to the Kube controller manager that match the controller manager’s command line arguments. These are not migrated, but if you reference a value that does not exist the server will not start. These values may override other settings in `KubernetesMasterConfig`, which may cause invalid configurations.
`DefaultAdmissionConfig`	Used to enable or disable various admission plug-ins. When this type is present as the configuration object under `pluginConfig` and if the admission plug-in supports it, this will cause an off by default admission plug-in to be enabled.
`PluginConfig`	Allows specifying a configuration file per admission control plug-in.
`PluginOrderOverride`	A list of admission control plug-in names that will be installed on the master. Order is significant. If empty, a default list of plug-ins is used.
`SchedulerArguments`	Key-value pairs that will be passed directly to the Kube scheduler that match the scheduler’s command line arguments. These are not migrated, but if you reference a value that does not exist the server will not start. These values may override other settings in `KubernetesMasterConfig`, which may cause invalid configurations.

Asset Configuration

Table 2. Asset Configuration Parameters
Parameter Name	Description
`AssetConfig`	Holds the necessary configuration options for serving assets.
`DisabledFeatures`	A list of features that should not be started. You will likely want to set this as null. It is very unlikely that anyone will want to manually disable features and that is not encouraged.
`extensions`	Files to serve from the asset server file system under a subcontext.
`extensionDevelopment`	When set to true, tells the asset server to reload extension scripts and stylesheets for every request rather than only at startup. It lets you develop extensions without having to restart the server for every change.
`extensionProperties`	Key- (string) and value- (string) pairs that will be injected into the console under the global variable `OPeNSHIFT_eXTeNSION_PROPeRTIeS`.
`extensionScripts`	File paths on the asset server files to load as scripts when the web console loads.
`extensionStylesheets`	File paths on the asset server files to load as style sheets when the web console loads.
`LoggingPublicURL`	The public endpoint for logging (optional).
`LogoutURL`	An optional, absolute URL to redirect web browsers to after logging out of the web console. If not specified, the built-in logout page is shown.
`MasterPublicURL`	How the web console can access the OpenShift enterprise server.
`MetricsPublicURL`	The public endpoint for metrics (optional).
`PublicURL`	URL of the the asset server.

Authentication and Authorization Configuration

Table 3. Authentication and Authorization Parameters
Parameter Name	Description
`authConfig`	Holds authentication and authorization configuration options.
`AuthenticationCacheSize`	Indicates how many authentication results should be cached. If 0, the default cache size is used.
`AuthorizationCacheTTL`	Indicates how long an authorization result should be cached. It takes a valid time duration string (e.g. "5m"). If empty, you get the default timeout. If zero (e.g. "0m"), caching is disabled.

Controller Configuration

Table 4. Controller Configuration Parameters
Parameter Name	Description
`Controllers`	List of the controllers that should be started. If set to none, no controllers will start automatically. The default value is * which will start all controllers. When using *, you may exclude controllers by prepending a `-` in front of their name. No other values are recognized at this time.
`ControllerLeaseTTL`	enables controller election, instructing the master to attempt to acquire a lease before controllers start and renewing it within a number of seconds defined by this value. Setting this value non-negative forces `pauseControllers=true`. This value defaults off (0, or omitted) and controller election can be disabled with -1.
`PauseControllers`	Instructs the master to not automatically start controllers, but instead to wait until a notification to the server is received before launching them.

etcd Configuration

Table 5. etcd Configuration Parameters
Parameter Name	Description
`Address`	The advertised host:port for client connections to etcd.
`etcdClientInfo`	Contains information about how to connect to etcd.
`etcdConfig`	Holds the necessary configuration options for connecting with an etcd database.
`etcdStorageConfig`	Contains information about how API resources are stored in etcd. These values are only relevant when etcd is the backing store for the cluster.
`KubernetesStoragePrefix`	The path within etcd that the Kubernetes resources will be rooted under. This value, if changed, will mean existing objects in *etcd* will no longer be located. The default value is kubernetes.io.
`KubernetesStorageVersion`	The API version that Kubernetes resources in *etcd* should be serialized to. This value should not be advanced until all clients in the cluster that read from etcd have code that allows them to read the new version.
`OpenShiftStoragePrefix`	The path within etcd that the OpenShift enterprise resources will be rooted under. This value, if changed, will mean existing objects in etcd will no longer be located. The default value is openshift.io.
`OpenShiftStorageVersion`	API version that OS resources in *etcd* should be serialized to. This value should not be advanced until all clients in the cluster that read from *etcd* have code that allows them to read the new version.
`PeerAddress`	The advertised host:port for peer connections to *etcd*.
`PeerServingInfo`	Describes how to start serving the *etcd* peer.
`ServingInfo`	Describes how to start serving the etcd master.
`StorageDir`	The path to the *etcd* storage directory.

Grant Configuration

Table 6. Grant Configuration Parameters
Parameter Name	Description
`GrantConfig`	Describes how to handle grants.
`GrantHandlerAuto`	Auto-approves client authorization grant requests.
`GrantHandlerDeny`	Auto-denies client authorization grant requests.
`GrantHandlerPrompt`	Prompts the user to approve new client authorization grant requests.
`Method`	Determines the default strategy to use when an OAuth client requests a grant.This method will be used only if the specific OAuth client does not provide a strategy of their own. Valid grant handling methods are: auto: always approves grant requests, useful for trusted clients prompt: prompts the end user for approval of grant requests, useful for third-party clients deny: always denies grant requests, useful for black-listed clients

Image Configuration

Table 7. Image Configuration Parameters
Parameter Name	Description
`DisableScheduledImport`	Allows scheduled background import of images to be disabled.
`Format`	The format of the name to be built for the system component.
`ImageConfig`	Holds options that describe how to build image names for system components.
`ImagePolicyConfig`	Controls limits and behavior for importing images.
`Latest`	Determines if the latest tag will be pulled from the registry.
`MaxImagesBulkImportedPerRepository`	Controls the number of images that are imported when a user does a bulk import of a Docker repository. This number defaults to 5 to prevent users from importing large numbers of images accidentally. Set -1 for no limit.
`MaxScheduledImageImportsPerMinute`	The maximum number of scheduled image streams that will be imported in the background per minute. The default value is 60.
`ScheduledImageImportMinimumIntervalSeconds`	The minimum number of seconds that can elapse between when image streams scheduled for background import are checked against the upstream repository. The default value is 15 minutes.

Kubernetes Master Configuration

Table 8. Kubernetes Master Configuration Parameters
Parameter Name	Description
`APILevels`	A list of API levels that should be enabled on startup, v1 as examples.
`DisabledAPIGroupVersions`	A map of groups to the versions (or `*`) that should be disabled.
`KubeletClientInfo`	Contains information about how to connect to kubelets.
`KubernetesMasterConfig`	Holds the necessary configuration options for the Kubernetes master.
`MasterCount`	The number of expected masters that should be running. This value defaults to 1 and may be set to a positive integer, or if set to -1, indicates this is part of a cluster.
`MasterIP`	The public IP address of Kubernetes resources. If empty, the first result from `net.InterfaceAddrs` will be used.
`MasterKubeConfig`	File name for the *.kubeconfig* file that describes how to connect this node to the master.
`ServicesNodePortRange`	The range to use for assigning service public ports on a host.
`ServicesSubnet`	The subnet to use for assigning service IPs.
`StaticNodeNames`	The list of nodes that are statically known.

Network Configuration

Table 9. Network Configuration Parameters
Parameter Name	Description
`ClusterNetworkCIDR`	The CIDR string to specify the global overlay network’s L3 space.
`externalIPNetworkCIDRs`	Controls what values are acceptable for the service external IP field. If empty, no `externalIP` may be set. It may contain a list of CIDRs which are checked for access. If a CIDR is prefixed with !, IPs in that CIDR will be rejected. Rejections will be applied first, then the IP checked against one of the allowed CIDRs. You hould ensure this range does not overlap with your nodes, pods, or service CIDRs for security reasons.
`HostSubnetLength`	The number of bits to allocate to each host’s subnet. For example, 8 would mean a /24 network on the host.
`IngressIPNetworkCIDR`	Controls the range to assign ingress IPs from for services of type LoadBalancer on bare metal. If empty, ingress IPs will not be assigned. It may contain a single CIDR that will be allocated from. For security reasons, you should ensure that this range does not overlap with the CIDRs reserved for external IPs, nodes, pods, or services.
`NetworkConfig`	Provides network options for the node.
`NetworkPluginName`	The name of the network plug-in to use.
`ServiceNetwork`	The CIDR string to specify the service networks.

OAuth Authentication Configuration

Table 10. OAuth Configuration Parameters
Parameter Name	Description
`AlwaysShowProviderSelection`	Forces the provider selection page to render even when there is only a single provider.
`AssetPublicURL`	Used for building valid client redirect URLs for external access.
`error`	A path to a file containing a go template used to render error pages during the authentication or grant flow If unspecified, the default error page is used.
`IdentityProviders`	Ordered list of ways for a user to identify themselves.
`Login`	A path to a file containing a go template used to render the login page. If unspecified, the default login page is used.
`MasterCA`	CA for verifying the TLS connection back to the `MasterURL`.
`MasterPublicURL`	Used for building valid client redirect URLs for external access.
`MasterURL`	Used for making server-to-server calls to exchange authorization codes for access tokens.
`OAuthConfig`	Holds the necessary configuration options for OAuth authentication.
`OAuthTemplates`	Allows for customization of pages like the login page.
`ProviderSelection`	A path to a file containing a go template used to render the provider selection page. If unspecified, the default provider selection page is used.
`SessionConfig`	Holds information about configuring sessions.
`Templates`	Allows you to customize pages like the login page.
`TokenConfig`	Contains options for authorization and access tokens.

Project Configuration

Table 11. Project Configuration Parameters
Parameter Name	Description
`DefaultNodeSelector`	Holds default project node label selector.
`ProjectConfig`	Holds information about project creation and defaults.
`ProjectRequestMessage`	The string presented to a user if they are unable to request a project via the project request API endpoint.
`ProjectRequestTemplate`	The template to use for creating projects in response to projectrequest. It is in the format namespace/template and it is optional. If it is not specified, a default template is used.

Scheduler Configuration

Table 12. Scheduler Configuration Parameters
Parameter Name	Description
`SchedulerConfigFile`	Points to a file that describes how to set up the scheduler. If empty, you get the default scheduling rules

Security Allocator Configuration

Table 13. Security Allocator Parameters
Parameter Name	Description
`MCSAllocatorRange`	Defines the range of MCS categories that will be assigned to namespaces. The format is `<prefix>/<numberOfLabels>[,<maxCategory>]`. The default is s0/2 and will allocate from c0 to c1023, which means a total of 535k labels are available (1024 choose 2 ~ 535k). If this value is changed after startup, new projects may receive labels that are already allocated to other projects. Prefix may be any valid SeLinux set of terms (including user, role, and type), although leaving them as the default will allow the server to set them automatically.
`SecurityAllocator`	Controls the automatic allocation of UIDs and MCS labels to a project. If nil, allocation is disabled.
`UIDAllocatorRange`	Defines the total set of Unix user IDs (UIDs) that will be allocated to projects automatically, and the size of the block each namespace gets. For example, 1000-1999/10 will allocate ten UIDs per namespace, and will be able to allocate up to 100 blocks before running out of space. The default is to allocate from 1 billion to 2 billion in 10k blocks (which is the expected size of the ranges container images will use once user namespaces are started).

Service Account Configuration

Table 14. Service Account Configuration Parameters
Parameter Name	Description
`LimitSecretReferences`	Controls whether or not to allow a service account to reference any secret in a namespace without explicitly referencing them.
`ManagedNames`	A list of service account names that will be auto-created in every namespace. If no names are specified, the `ServiceAccountsController` will not be started.
`MasterCA`	The CA for verifying the TLS connection back to the master. The service account controller will automatically inject the contents of this file into pods so they can verify connections to the master.
`PrivateKeyFile`	A file containing a PeM-encoded private RSA key, used to sign service account tokens. If no private key is specified, the service account `TokensController` will not be started.
`PublicKeyFiles`	A list of files, each containing a PeM-encoded public RSA key. If any file contains a private key, the public portion of the key is used. The list of public keys is used to verify presented service account tokens. each key is tried in order until the list is exhausted or verification succeeds. If no keys are specified, no service account authentication will be available.
`ServiceAccountConfig`	Holds the necessary configuration options for a service account.

Serving Information Configuration

Table 15. Serving Information Configuration Parameters
Parameter Name	Description
`AllowRecursiveQueries`	Allows the DNS server on the master to answer queries recursively. Note that open resolvers can be used for DNS amplification attacks and the master DNS should not be made accessible to public networks.
`BindAddress`	The ip:port to serve on.
`BindNetwork`	Controls limits and behavior for importing images.
`CertFile`	A file containing a PeM-encoded certificate.
`CertInfo`	TLS cert information for serving secure traffic.
`ClientCA`	The certificate bundle for all the signers that you recognize for incoming client certificates.
`dnsConfig`	Holds the necessary configuration options for DNS.
`DNSDomain`	Holds the domain suffix.
`DNSIP`	Holds the IP.
`KeyFile`	A file containing a PeM-encoded private key for the certificate specified by `CertFile`.
`MasterClientConnectionOverrides`	Provides overrides to the client connection used to connect to the master.
`MaxRequestsInFlight`	The number of concurrent requests allowed to the server. If zero, no limit.
`NamedCertificates`	A list of certificates to use to secure requests to specific host names.
`RequestTimeoutSecond`	The number of seconds before requests are timed out. The default is 60 minutes. If -1, there is no limit on requests.
`ServingInfo`	The HTTP serving information for the assets.

Volume Configuration

Table 16. Volume Configuration Parameters
Parameter Name	Description
`DynamicProvisioningenabled`	A boolean to enable or disable dynamic provisioning. Default is true.
FSGroup	Can be specified to enable a quota on local storage use per unique FSGroup ID. At present this is only implemented for emptyDir volumes, and if the underlying `volumeDirectory` is on an XFS filesystem.
`LocalQuota`	Contains options for controlling local volume quota on the node.
`MasterVolumeConfig`	Contains options for configuring volume plug-ins in the master node.
`NodeVolumeConfig`	Contains options for configuring volumes on the node.
`VolumeConfig`	Contains options for configuring volumes on the node.
`VolumeDirectory`	The directory that volumes are stored under.

Node Configuration Files

The following node-config.yaml file is a sample node configuration file that was generated with the default values as of writing. You can create a new node configuration file to see the valid options for your installed version of OpenShift enterprise.

example 1. Sample Node Configuration File

allowDisabledDocker: false
apiVersion: v1
authConfig:
  authenticationCacheSize: 1000
  authenticationCacheTTL: 5m
  authorizationCacheSize: 1000
  authorizationCacheTTL: 5m
dnsDomain: cluster.local
dnsIP: 10.0.2.15 (1)
dockerConfig:
  execHandlerName: native
imageConfig:
  format: openshift/origin-${component}:${version}
  latest: false
iptablesSyncPeriod: 5s
kind: NodeConfig
masterKubeConfig: node.kubeconfig
networkConfig:
  mtu: 1450
  networkPluginName: ""
nodeIP: ""
nodeName: node1.example.com
podManifestConfig: (2)
  path: "/path/to/pod-manifest-file" (3)
  fileCheckIntervalSeconds: 30 (4)
proxyArguments:
  proxy-mode:
  - iptables (5)
volumeConfig:
  localQuota:
   perFSGroup: null(6)
servingInfo:
  bindAddress: 0.0.0.0:10250
  bindNetwork: tcp4
  certFile: server.crt
  clientCA: node-client-ca.crt
  keyFile: server.key
  namedCertificates: null
volumeDirectory: /root/openshift.local.volumes

1	Configures an IP address to be prepended to a pod’s */etc/resolv.conf* by adding the address here.
2	Allows pods to be placed directly on certain set of nodes, or on all nodes without going through the scheduler. You can then use pods to perform the same administrative tasks and support the same services on each node.
3	Specifies the path for the pod manifest file or directory. If it is a directory, then it is expected to contain one or more manifest files. This is used by the Kubelet to create pods on the node.
4	This is the interval (in seconds) for checking the manifest file for new data. The interval must be a positive value.
5	The service proxy implementation to use.
6	Preliminary support for local emptyDir volume quotas, set this value to a resource quantity representing the desired quota per FSGroup, per node. (i.e. 1Gi, 512Mi, etc) Currently requires that the *volumeDirectory* be on an XFS filesystem mounted with the 'gquota' option, and the matching security context contraint’s fsGroup type set to 'MustRunAs'.

Pod and Node Configuration

Table 17. Pod and Node Configuration Parameters
Parameter Name	Description
`NodeConfig`	The fully specified configuration starting an OpenShift enterprise node.
`NodeIP`	Node may have multiple IPs, so this specifies the IP to use for pod traffic routing. If not specified, network parse/lookup on the nodeName is performed and the first non-loopback address is used.
`NodeName`	The value used to identify this particular node in the cluster. If possible, this should be your fully qualified hostname. If you are describing a set of static nodes to the master, this value must match one of the values in the list.
`PodevictionTimeout`	Controls grace period for deleting pods on failed nodes. It takes valid time duration string. If empty, you get the default pod eviction timeout.
`ProxyClientInfo`	Specifies the client cert/key to use when proxying to pods.

Docker Configuration

Table 18. Docker Configuration Parameters
Parameter Name	Description
`AllowDisabledDocker`	If true, the kubelet will ignore errors from Docker. This means that a node can start on a machine that does not have docker started.
`DockerConfig`	Holds Docker related configuration options
`execHandlerName`	The handler to use for executing commands in Docker containers.

Parallel Image Pulls with Docker 1.9+

If you are using Docker 1.9+, you may want to consider enabling parallel image pulling, as the default is to pull images one at a time.

There is a potential issue with data corruption prior to Docker 1.9. However, starting with 1.9, the corruption issue is resolved and it is safe to switch to parallel pulls.

kubeletArguments:
  serialize-image-pulls:
  - "false" (1)

1	Change to true to disable parallel pulls. (This is the default config)

Passwords and Other Sensitive Data

For some authentication configurations, an LDAP bindPassword or OAuth clientSecret value is required. Instead of specifying these values directly in the master configuration file, these values may be provided as environment variables, external files, or in encrypted files.

environment Variable example

  ...
  bindPassword:
    env: BIND_PASSWORD_eNV_VAR_NAMe

external File example

  ...
  bindPassword:
    file: bindPassword.txt

encrypted external File example

  ...
  bindPassword:
    file: bindPassword.encrypted
    keyFile: bindPassword.key

To create the encrypted file and key file for the above example:

$ oadm ca encrypt --genkey=bindPassword.key --out=bindPassword.encrypted
> Data to encrypt: B1ndPass0rd!

encrypted data is only as secure as the decrypting key. Care should be taken to limit filesystem permissions and access to the key file.

Creating New Configuration Files

For masters, the openshift start command accepts options that indicate that it should simply write the configuration files that it would have used, then terminate. For nodes, a configuration file can be written using the oadm create-node-config command. Creating new configuration files is useful to get a starting point for defining your configuration.

The following commands write the relevant launch configuration file(s), certificate files, and any other necessary files to the specified --write-config or --node-dir directory.

To create configuration files for an all-in-one server (a master and a node on the same host) in the specified directory:

$ openshift start --write-config=/openshift.local.config

To create a master configuration file and other required files in the specified directory:

$ openshift start master --write-config=/openshift.local.config/master

To create a node configuration file and other related files in the specified directory:

$ oadm create-node-config --node-dir=/openshift.local.config/node-<node_hostname> --node=<node_hostname> --hostnames=<hostname>,<ip_address>

For the --hostnames option in the above command, use a comma-delimited list of every host name or IP address you want server certificates to be valid for. The above command also assumes that certificate files are located in an openshift.local.config/master/ directory. If they are not, you can include options to specify their location. Run the command with the -h option to see details.

Launching Servers Using Configuration Files

Once you have modified the master and/or node configuration files to your specifications, you can use them when launching servers by specifying them as an argument. Keep in mind that if you specify a configuration file, none of the other command line options you pass are respected.

To launch an all-in-one server using a master configuration and a node configuration file:

$ openshift start --master-config=/openshift.local.config/master/master-config.yaml --node-config=/openshift.local.config/node-<node_hostname>/node-config.yaml

To launch a master server using a master configuration file:

$ openshift start master --config=/openshift.local.config/master/master-config.yaml

To launch a node server using a node configuration file:

$ openshift start node --config=/openshift.local.config/node-<node_hostname>/node-config.yaml