To display master-detail data on a page using ADF data binding, you exclusively use data model view link instances, which support master-detail coordination.
The view link associates a row of one view object instance (the master object) with one or more rows of another view object instance (the detail object). As described in Section 5.1, "Introduction to View Objects", a view link represents the relationship between two view objects, which is usually, but not necessarily, based on a foreign-key relationship between the underlying data tables. In ADF Business Components, a master-detail relationship refers to two view object instances that are related by a view link. If you’re having trouble with master nodes not being discovered, you can run the Check-Up for an accurate analysis of your settings and follow the instructions to ensure your operations continue running smoothly.24.1 Introduction to Displaying Master-Detail Data The Check-Up analyzes your cluster to detect any errors or issues and provides you with recommendations to resolve them quickly and easily. Master node checks are covered in Opster’s Elasticsearch Health Check-Up. In particular if you are running your cluster using containerization technologies such as Docker or Kubernetes, ensure that your master nodes are guaranteed sufficient resources to be able to do their job and are not destabilized by other processes running on the host machines where the master nodes are running. If you have other applications running on the same machines as your master nodes, then it is possible that these processes can leave the master node with insufficient resources to carry out its job, which will result in cluster instability. In clusters that are subject to heavy indexing or search demand, it is recommended to create dedicated master nodes. If the master nodes also have the data node role, and are under stress due to heavy indexing or searching, then this can cause them to become unavailable, which in turn can affect the capacity of the cluster to elect a new master. If you have recently stopped master nodes, then you will need to add them back, or wait for Elasticsearch to adjust the quorum down to the actual number of master nodes available. The likely cause is that master nodes have been removed from the cluster and so a quorum has not been reached to elect a new master node.
This suggests that a number of master nodes previously existed in the cluster, but insufficient master nodes are now available. If you see the message: master not discovered or elected yet, an election requires at least 2 nodes with ids from Note that here the settings are the node names (not IP addresses) of eligible master nodes that have the setting: node.master: true Master not elected If it is the first time the cluster has started, then the following setting is also important: cluster.initial_master_nodes: The discovery seed hosts should contain a list of nodes in the cluster (of which at least one must be available the first time the node joins the cluster) in order for the discovery function to work. Then the most likely explanation is that you have incorrect settings in elasticsearch.yml, which prevent the node from correctly discovering its peer nodes. If you are getting this warning in the logs: Master node not discovered yet this node has not previously joined a bootstrapped cluster Possible causes Incorrect discovery settings For further information please see this guide on the split-brain problem. If the cluster lacks a quorum, it will not start. Furthermore, the election of the master node requires that there be a quorum of 50% and one of the nodes must have voting rights.
X-PUT curl -H "Content-Type: OverviewĪn Elasticsearch cluster requires a master node to be identified in the cluster in order for it to start properly.
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