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49 lines
1.7 KiB
ReStructuredText
49 lines
1.7 KiB
ReStructuredText
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High Availability
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=================
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This section describes how to make a Corda node highly available.
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Hot Cold
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~~~~~~~~
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In the hot cold configuration, failover is handled manually, by promoting the cold node after the former hot node
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failed or was taken offline for maintainance.
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RPC clients have to handle ``RPCException`` and implement application specific recovery and retry.
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Prerequisites
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-------------
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* A load-balancer for P2P, RPC and web traffic
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* A shared file system for the artemis and certificates directories
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* A shared database, e.g. Azure SQL
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The hot-cold deployment consists of two Corda nodes, a hot node that is currently handling request and running flows
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and a cold backup node that can take over, if the hot node fails or is taken offline for an upgrade. Both nodes should
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be able to connect to a shared database and a replicated file-system hosting the artemis and certificates directories.
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The hot-cold ensemble should be fronted by a load-balancer for P2P, web and RPC traffic. The load-balancer should do
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health monitoring and route the traffic to the node that is currently active. To prevent data corruption in case of
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accidental simultaneous start of both nodes, the current hot node takes a leader lease in the form of a mutual exclusion
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lock implemented by a row in the shared database.
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Configuration
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-------------
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The configuration snippet below shows the relevant settings.
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.. sourcecode:: none
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enterpriseConfiguration = {
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mutualExclusionConfiguration = {
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on = true
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machineName = ${HOSTNAME}
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updateInterval = 20000
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waitInterval = 40000
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}
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}
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Hot Warm
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~~~~~~~~
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In the future we are going to support automatic failover.
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