chatman commented on a change in pull request #403: URL: https://github.com/apache/solr/pull/403#discussion_r779831163
########## File path: solr/solr-ref-guide/src/node-roles.adoc ########## @@ -0,0 +1,198 @@ += Node Roles +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +A node in Solr is usually capable of performing various types of operations, e.g. hosting replicas, performing indexing and querying on them, collection management tasks etc. However, if someone wants to setup a cluster where these functionalities are isolated to certain dedicated nodes, then this can be achieved leveraging the concept of node roles. + +== Definitions + +=== Node role + +A role is a designation of a node that indicates that the node may perform a certain functionality that is governed by the role. + +=== Mode +Every role has a list of modes under which a node can be. It can be simple (e.g. `["on", "off"]`) or more granular (e.g. `["allowed", "preferred", "disallowed"]`). + +== Roles + +In order to specify role(s) for a node, one needs to start a Solr node with the following parameter. + +.Startup Parameter +[cols="1,2,1,1"] +|=== +|Parameter |Value |Required? | Default + +|solr.node.roles +|Comma separated list of roles (in the format: `<role>:<mode>`) for this node. +Examples: `-Dsolr.node.roles=data:on,overseer:allowed` or `-Dsolr.node.roles=overseer:preferred` +|No +|`data:on,overseer:allowed` +|=== + +[TIP] +==== +If a node has been started with no `solr.node.roles` parameter, it will be assumed to have the data role turned on and overseer role allowed on it. If you've never used roles before, you likely won't need to change anything in your startup parameters to accomodate the functionality associated with these roles. +==== + +.Supported roles Review comment: There is no concept of a default mode for a role. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
