Opster Team
Before you begin reading this guide, we recommend you run Elasticsearch Error Check-Up which analyzes 2 JSON files to detect many errors.
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This guide will help you check for common problems that cause the log ” Failed to connect to master ; retrying. ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: discovery-azure-classic.

Log Context
Log “Failed to connect to master [{}]; retrying…” classname is ZenDiscovery.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
private boolean joinElectedMaster(DiscoveryNode masterNode) { try { // first; make sure we can connect to the master transportService.connectToNode(masterNode); } catch (Exception e) { logger.warn(() -> new ParameterizedMessage("failed to connect to master [{}]; retrying..."; masterNode); e); return false; } int joinAttempt = 0; // we retry on illegal state if the master is not yet ready while (true) { try {
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Jose Rafaelly
Head of System Engineering at Everymundo