[SOLR-12641] Support rolling updates when jira/http2 get merged

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Assignee: Cao Manh Dat
• Reporter: Cao Manh Dat
• Created: 08/Aug/18 08:37
• Updated: 02/Oct/19 17:23
• Resolved: 10/Sep/18 08:16

Description

Right now, Http2SolrClient can't connect to old Solr nodes, this seems an issue of Jetty HTTP client (https://github.com/eclipse/jetty.project/issues/1308). To support rolling updates, this problem must be solved.

After discussing with other guys, we agree that rolling updates can be no support in Solr 8.0 with default settings since it is a major release. Users who want to do rolling updates must follow these two steps.

• Upgrade nodes will start with a special flag to indicate that they will use HTTP/1.1 as the protocol for intercommunication.
• When all nodes are in version 8.0, restart nodes and remove above special flag, therefore nodes will communicate with others using HTTP/2 from thereafter.

This issue will aim to introduce that special flag. Note that by default HTTP/2 still the default protocol for Solr 8.0.

Issue Links

• is related to: SOLR-12639 Umbrella JIRA for adding support HTTP/2, jira/http2
• links to: Jetty #1350: query server to select HTTP version protocol