Be aware of the following important considerations for WebLogic domains running in Kubernetes:
Domain Home Location: The WebLogic domain home location is determined by the domain resource domainHome and domainHomeInImage fields.
If you are using 3.0.0-rc1, these same fields are used, if specified; otherwise, a default location is determined by the domainHomeSourceType setting.
The domainHomeSourceType field is not available in releases before 3.0.0-rc1.
domainHome field is not specified and domainHomeSourceType is Image (the default), then the operator will assume that the domain home is a directory under /u01/oracle/user_projects/domains/, and report an error if no domain is found or more than one domain is found.domainHome field is not specified and domainHomeSourceType is PersistentVolume, then the operator will assume that the domain home is /shared/domains/DOMAIN_UID.domainHome field is not specified and the domainHomeSourceType is FromModel, then the operator will assume that the domain home is /u01/domains/DOMAIN_UID.Oracle strongly recommends storing an image containing a WebLogic domain home (domainHomeSourceType is Image)
as private in the registry (for example, Oracle Cloud Infrastructure Registry, Docker Hub, and such).
A Docker image that contains a WebLogic domain has sensitive information including
keys and credentials that are used to access external resources (for example, the data source password).
For more information, see
WebLogic domain in Docker image protection.
Log File Locations: The operator can automatically override WebLogic domain and server log locations using
configuration overrides. This occurs if the domain resource logHomeEnabled field is explicitly set to true, or if logHomeEnabled isn’t set
and domainHomeSourceType is set to PersistentVolume. When overriding, the log location will be the location specified by the logHome setting.
Listen Address Overrides: The operator will automatically override all WebLogic domain default,
SSL, admin, or custom channel listen addresses (using situational configuration overrides). These will become domainUID followed by a
hyphen and then the server name, all lower case, and underscores converted to hyphens. For example, if domainUID=domain1 and
the WebLogic Server name is Admin_Server, then its listen address becomes domain1-admin-server.
Domain, Cluster, Server, and Network-Access-Point Names: WebLogic domain, cluster, server, and network-access-point (channel)
names must contain only the characters A-Z, a-z, 0-9, -, or _. This ensures that they can be converted to
meet Kubernetes resource and DNS1123 naming requirements. (When generating pod and service names, the operator will convert
configured names to lower case and substitute a hyphen (-) for each underscore (_).)
Node Ports: If you choose to expose any WebLogic channels outside the Kubernetes cluster using a NodePort, for example, the
administration port or a T3 channel to allow WLST access, you need to ensure that you allocate each channel a
unique port number across the entire Kubernetes cluster. If you expose the administration port in each WebLogic domain in
the Kubernetes cluster, then each one must have a different port number. This is required because NodePorts are used to
expose channels outside the Kubernetes cluster.
Exposing administrative, RMI, or T3 capable channels using a Kubernetes NodePort
can create an insecure configuration. In general, only HTTP protocols should be made available externally and this exposure
is usually accomplished by setting up an external load balancer that can access internal (non-NodePort) services.
For more information, see T3 channels.
Host Path Persistent Volumes: If using a hostPath persistent volume, then it must be available on all worker nodes in the cluster and have read/write/many permissions for all container/pods in the WebLogic Server deployment. Be aware
that many cloud provider’s volume providers may not support volumes across availability zones. You may want to use NFS or a clustered file system to work around this limitation.
Security Note: The USER_MEM_ARGS environment variable defaults to -Djava.security.egd=file:/dev/./urandom in all WebLogic Server pods and the WebLogic introspection job. It can be explicitly set to another value in your domain resource YAML file using the env attribute under the serverPod configuration.
JVM Memory and Java Option Arguments: The following environment variables can be used to customize the JVM memory and Java options for both the WebLogic Server Managed Servers and Node Manager instances:
JAVA_OPTIONS - Java options for starting WebLogic ServerUSER_MEM_ARGS - JVM memory arguments for starting WebLogic ServerNODEMGR_JAVA_OPTIONS - Java options for starting a Node Manager instanceNODEMGR_MEM_ARGS - JVM memory arguments for starting a Node Manager instanceFor more information, see Domain resource.
The following features are not certified or supported in this release:
For up-to-date information about the features of WebLogic Server that are supported in Kubernetes environments, see My Oracle Support Doc ID 2349228.1.
You can locate a WebLogic domain either in a persistent volume (PV) or in a Docker image. For examples of each, see the WebLogic Server Kubernetes Operator samples.
If you want to create your own Docker images, for example, to choose a specific set of patches or to create a domain with a specific configuration or applications deployed, then you can create the domain custom resource manually to deploy your domain. This process is documented in this sample.
You can modify the WebLogic domain configuration for Domain in PV, Domain in Image, and Model in Image before deploying a domain resource:
When the domain is in a persistent volume, you can use WLST or WDT to change the configuration.
For Domain in Image and Domain in PV you can use configuration overrides.
Configuration overrides allow changing a configuration without modifying its original config.xml or system resource XML files, and supports
parameterizing overrides so that you can inject values into them from Kubernetes Secrets. For example, you can inject database user names, passwords,
and URLs that are stored in a secret.
For Model in Image you use Runtime Updates.
For more information, see Domain resource.
You can perform lifecycle operations on WebLogic Servers, clusters, or domains. See Starting and stopping and Restarting servers.
The operator let’s you initiate scaling of clusters in various ways: