{"id":5392,"date":"2012-07-20T08:09:59","date_gmt":"2012-07-20T13:09:59","guid":{"rendered":"http:\/\/jianmingli.com\/wp\/?p=5392"},"modified":"2012-08-25T23:07:12","modified_gmt":"2012-08-26T04:07:12","slug":"1z0-102-managing-clusters","status":"publish","type":"post","link":"https:\/\/jianmingli.com\/wp\/?p=5392","title":{"rendered":"Managing WebLogic 11g Clusters"},"content":{"rendered":"
\n

Contents<\/h2>\n
    \n\t
  1. \n\t\tDeploy an application to a cluster<\/a>\n\t<\/li>\n\t
  2. \n\t\tDescribe the replication of a session state in a cluster<\/a>\n\t\t
      \n\t\t\t
    1. \n\t\t\t\tHTTP Session Replication<\/a>\n\t\t\t<\/li>\n\t\t\t
    2. \n\t\t\t\tIn Memory Replication<\/a>\n\t\t\t<\/li>\n\t\t<\/ol>\n\t
    3. \n\t\tConfigure replication groups<\/a>\n\t<\/li>\n\t
    4. \n\t\tConfigure in-memory session replication<\/a>\n\t<\/li>\n\t
    5. \n\t\tConfigure Java Database Connectivity (JDBC) session replication<\/a>\n\t\t
        \n\t\t\t
      1. \n\t\t\t\tConfigure JDBC Persistence<\/a>\n\t\t\t<\/li>\n\t\t<\/ol>\n\t
      2. \n\t\tConfigure file session replication<\/a>\n\t\t
          \n\t\t\t
        1. \n\t\t\t\tHTTP State Management Best Practices<\/a>\n\t\t\t<\/li>\n\t\t<\/ol>\n\t
        2. \n\t\tDescribe state replication for stateful session EJBs<\/a>\n\t\t
            \n\t\t\t
          1. \n\t\t\t\tConfigure Deployment Descriptors<\/a>\n\t\t\t<\/li>\n\t\t\t
          2. \n\t\t\t\tConfigure EJB Clustering using Admin Console<\/a>\n\t\t\t<\/li>\n\t\t\t
          3. \n\t\t\t\tEJB Best Practices<\/a>\n\t\t\t<\/li>\n<\/ol>\n<\/ol>\n<\/ol>\n<\/div>\n
             <\/div>\n

            << Previous<\/a><\/p>\n

            Deploy an application to a cluster<\/h2><\/span>\n

            * Applications are deployed using the two phase deployment (TPD) approach:
            \n– phase 1: distribute components\/modules to all server instances
            \n– phase 2: if phase 1 succeed, applications are deployed to allow client access
            \n* Relaxed deployment mode:
            \n– if one or more server instances are not available\/reachable (these servers are called partitioned server), deployment continues to available server instances
            \n– when partitioned servers become reachable, deployment starts on these servers (potential performance hit)
            \n* Relaxed deployment mode can be disabled by setting enforceClusterConstraints<\/em> to true with weblogic.Deployer<\/em>
            \n* Production redeployment in a cluster
            \n– may result in both older and new versions running simultaneously
            \n– older version always fails to same older version (fail if none exists)<\/p>\n

            \"\"<\/a><\/h6><\/span>\n

            Describe the replication of a session state in a cluster<\/h2><\/span>\n

            HTTP Session Replication<\/h3><\/span>\n

            * Supports:
            \n– in-memory replication: each user session always exists in two servers (primary and secondary servers)
            \n– JDBC persistence
            \n– file persistence
            \n* Configured within each web application
            \n– in weblogic.xml<\/em>: session-descriptor<\/em>
            \n* All web servers should have identical configuration
            \n* WLS also supports AsyncRep<\/em> to improve cluster performance<\/p>\n

            In Memory Replication<\/h3><\/span>\n

            * WLS supports in memory replication for:
            \n– HttpSession objects
            \n– Statefull session beans
            \n* Session objects exist only on two servers: primary server and secondary server
            \n* Primary\/secondary servers are determined by replication group and machine definition
            \n* Clients must access the cluster using one of the following:
            \n– WLS aware<\/em> hardware load balancer: LB must support SSL persistence and passive cookie persistence to allow cookie persistence between client and WLS
            \n– OHS with mod_wl_ohs<\/em>
            \n– One or more web servers with WebLogic proxy plug-ins<\/em> configured identically (WebLogic proxy plug-ins only<\/strong> supports round robin load balancing)
            \n– Oracle WebLogic Server configured with HTTPClusterServlet<\/em><\/p>\n

            Configure replication groups<\/h2><\/span>\n

            * Logical grouping of related servers in a cluster
            \n* Used to decide where to put in-memory backup objects (preferred replication group<\/em>)
            \n* Better than using machines since one physical computer may have multiple IP addresses (machines)<\/p>\n

            \"\"<\/a><\/h6><\/span>\n

            Configure in-memory session replication<\/h2><\/span>\n

            * Use weblogic.xml<\/em>:<\/p>\n

            \r\n\r\n  replicated<\/persistent-store-type>\r\n<\/session-descriptor>\r\n<\/pre>\n
            * persistent-store-type:
            \n– memory: Disables persistent session storage.
            \n– replicated: Same as memory, but session data is replicated across the clustered servers.
            \n– replicated_if_clustered: If the Web application is deployed on a clustered server, the in-effect persistent-store-type will be replicated. Otherwise, memory is the default.
            \n– async-replicated: Enables asynchronous session replication in an application or web application. See Configuring Session Persistence.
            \n– async-replicated-if-clustered: Enables asynchronous session replication in an application or web application when deployed to a cluster environment. If deployed to a single server environment, then the – – session persistence\/replication defaults to in-memory. This allows testing on a single server without deployment errors.
            \n– file: Uses file-based persistence (See also persistent-store-dir).
            \n– async-jdbc: Enables asynchronous JDBC persistence for HTTP sessions in an application or web application. See Configuring Session Persistence.
            \n– jdbc: Uses a database to store persistent sessions. (see also persistent-store-pool).
            \n– cookie: All session data is stored in a cookie in the user\u2019s browser.<\/p>\n
            Configure Java Database Connectivity (JDBC) session replication<\/h2><\/span>\n
            * Advantages:
            \n– No primary\/secondary needed.
            \n– All<\/strong> members of a cluster have access to any client’s session data
            \n* Disadvantages:
            \n– Performance hit<\/p>\n
            \"\"<\/a><\/h6><\/span>\n
            Configure JDBC Persistence<\/h3><\/span>\n
            * Create required wl_servlet_sessions<\/strong> table in database:<\/p>\n
            \r\ncreate table wl_servlet_sessions ( \r\nwl_id VARCHAR2(100) NOT NULL,\r\nwl_context_path VARCHAR2(100) NOT NULL, \r\nwl_is_new CHAR(1),\r\nwl_create_time NUMBER(20), \r\nwl_is_valid CHAR(1), \r\nwl_session_values LONG RAW, \r\nwl_access_time NUMBER(20),\r\nwl_max_inactive_interval\r\nINTEGER, PRIMARY KEY (wl_id, wl_context_path) );\r\n<\/pre>\n
            * Create JDBC data source that has read\/write privileges to the database
            \n* Configure weblogic.xml<\/em>:<\/p>\n
            \r\n\r\n  jdbc<\/persistent-store-type>\r\n  MyDataSource<\/persistent-store-pool>\r\n<\/session-descriptor>\r\n<\/pre>\n
            Configure file session replication<\/h2><\/span>\n
            * Create a folder shared by all servers on the cluster on a HA file system
            \n* Assign read\/write privileges to the folder
            \n* Configure weblogic.xml<\/p>\n
            \r\n\r\n  file<\/persistent-store-type>\r\n  \/mnt\/wls_share<\/persistent-store-dir>\r\n<\/session-descriptor>\r\n<\/pre>\n
            HTTP State Management Best Practices<\/h3><\/span>\n
            * Create WLS machines
            \n* Use Replication Groups
            \n* Choose replication strategy
            \n* Use ServerDebugConfig<\/em> MBean to debug session replication
            \n* Ensure objects are serializable<\/p>\n
            Describe state replication for stateful session EJBs<\/h2><\/span>\n
            * Achieved via replica-aware stubs
            \n* Replica-aware stubs are generated at compile time for clusterable EJBs
            \n* Supported algorithms:
            \n– round robin
            \n– weight based
            \n– random
            \n– parameter based (custom programming)
            \n* Also uses server affinity so that calls to objects remain with the same server<\/p>\n
            Configure Deployment Descriptors<\/h3><\/span>\n
            * For EJB 2, configure in weblogic-ejb-jar.xml<\/em> or weblogic-cmp-rdbms-jar.xml<\/em>:<\/p>\n
            \r\n\r\n  True<\/stateless-bean-is-clusterable>\r\n  random<\/stateless-bean-load-algorithm>\r\n<\/stateless-clustering>\r\n<\/pre>\n
            * For pure EJB 3, use deployment plan
            \n* For EJB 3 that supports backward compatibility with EJB 2, configure like EJB 2
            \n* Stateless session bean in weblogic-ejb-jar.xml<\/em><\/p>\n
            \r\n\r\n  \r\n  \r\n    True<\/stateless-bean-is-clusterable>\r\n    random<\/stateless-bean-load-algorithm>\r\n    \r\n  <\/stateless-clustering>\r\n<\/pre>\n
            * Stateful session bean in weblogic-ejb-jar.xml<\/em><\/p>\n
            \r\n\r\n  \r\n    true<\/home-is-clusterable>\r\n    random<\/home-load-algorithm>\r\n    ....\r\n    \r\n    InMemory<\/replication-type>\r\n  <\/stateful-session-clustering>\r\n<\/stateful-session-descriptor>\r\n<\/pre>\n
            * Entity bean in weblogic-ejb-jar.xml<\/em><\/p>\n
            \r\n\r\n  True<\/home-is-clusterable>\r\n  random<\/home-load-algorithm>\r\n  beanRouter<\/home-call-router-class-name>\r\n<\/entity-clustering>\r\n<\/pre>\n
            Configure EJB Clustering using Admin Console<\/h3><\/span>\n
            * Configures default EJB cluster settings for the domain<\/p>\n
            \"\"<\/a><\/h6><\/span>\n
            EJB Best Practices<\/h3><\/span>\n
            * Set pool and cache sizes accordingly
            \n* Cache size affects all<\/strong> nodes in the cluster
            \n* Mark bean as idempotent at either bean or method level in weblogic-ejb-jar.xml<\/em>
            \n– bean level:<\/p>\n
            \r\ntrue<\/stateless-bean-methods-are-idempotent>\r\n<\/pre>\n
            – method level:<\/p>\n
            \r\ntrue<\/dempotent-methods>\r\n<\/pre>\n
            Next <\/a>>><\/p>\n
            [mv_include id=’3268′]<\/p>\n","protected":false},"excerpt":{"rendered":"
            True random * Stateful session bean in weblogic-ejb-jar.xml true random …. InMemory * Entity bean in weblogic-ejb-jar.xml True random beanRouter Configure EJB Clustering using Admin Console * Configures default EJB cluster settings for the domain EJB Best Practices * Set … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[107,104],"tags":[588,180,157,185,167],"class_list":["post-5392","post","type-post","status-publish","format-standard","hentry","category-certification","category-weblogic11g","tag-11g","tag-1z0-102","tag-cluster","tag-manage","tag-wls"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p8cRUO-1oY","_links":{"self":[{"href":"https:\/\/jianmingli.com\/wp\/index.php?rest_route=\/wp\/v2\/posts\/5392","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jianmingli.com\/wp\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jianmingli.com\/wp\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jianmingli.com\/wp\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/jianmingli.com\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5392"}],"version-history":[{"count":12,"href":"https:\/\/jianmingli.com\/wp\/index.php?rest_route=\/wp\/v2\/posts\/5392\/revisions"}],"predecessor-version":[{"id":5710,"href":"https:\/\/jianmingli.com\/wp\/index.php?rest_route=\/wp\/v2\/posts\/5392\/revisions\/5710"}],"wp:attachment":[{"href":"https:\/\/jianmingli.com\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5392"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jianmingli.com\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5392"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jianmingli.com\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5392"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}