# Network heartbeat configuration This page describes how to configure the network heartbeat with Aerospike’s heartbeat protocols. Aerospike’s heartbeat protocols are responsible for maintaining cluster integrity. There are two supported heartbeat modes: - Multicast (UDP) - Mesh (TCP) ## Cloud consideration - **Lack of multicast support**: Cloud providers, such as, Amazon and Google Compute Engine do not support multicast networking. For these providers, use [Mesh heartbeats](https://aerospike.com/docs/database/manage/network/heartbeat#mesh-unicast-heartbeat), which uses point-to-point TCP connections for heartbeats. - **Network variability**: Often, the network latency on cloud platforms is not consistent over time. This can cause problems with heartbeat packet delivery times. For these providers, we recommend setting the heartbeat `interval` to 150 and the heartbeat `timeout` to 20. - **Instance pauses**: At times, your cloud instance could be paused by the cloud provider for short durations. For example, Google Compute Engine (GCE) employs [live migration](http://googlecloudplatform.blogspot.in/2015/03/Google-Compute-Engine-uses-Live-Migration-technology-to-service-infrastructure-without-application-downtime.html) which could pause your instance for short time durations for maintenance or software updates. The short pauses might cause the other instances in the cluster to consider this instance as “dead”. ## Multicast heartbeat For various reasons your network may not support multicast. See our [troubleshooting guide](https://aerospike.com/docs/database/advanced/troubleshoot) for information on how to validate multicast in your environment. ::: note The following values are deprecated in Database 8.1.0: - ‘multicast’ as a heartbeat `mode` - defining an `address` for the heartbeat ::: ### Configuration steps In the heartbeat sub-stanza: 1. Set `mode` to `multicast`. 2. Set `multicast-group` to a valid multicast address (239.0.0.0-239.255.255.255). 3. (Optional) Set `address` to the IP of the interface intended for intracluster communication. This setting also controls the interface fabric will use. Needed when isolating intra-cluster traffic to a particular network interface. 4. Set `interval` and `timeout` - `interval` (recommended: 150) controls how often to send a heartbeat packet. - `timeout` (recommended: 10) controls the number of intervals after which a node is considered to be missing by rest of nodes in the cluster if they haven’t received the heartbeat from missing node. - With the default settings, a node will be aware of another node leaving the cluster within 1.5 seconds. ### Example Terminal window ```bash ... heartbeat { mode multicast # Send heartbeats using Multicast multicast-group 239.1.99.2 # multicast address port 9918 # multicast port address 192.168.1.100 # (Optional) (Default any) IP of the NIC to # use to send out heartbeat and bind # fabric ports interval 150 # Number of milliseconds between heartbeats timeout 10 # Number of heartbeat intervals to wait # before timing out a node } ... ``` ## Mesh (Unicast) heartbeat Mesh uses TCP point to point connections for heartbeats. Each node in the cluster maintains a heartbeat connection to all other nodes, resulting in many connections required for mesh. For this reason, we recommend using multicast heartbeat protocol when available. - Mesh heartbeat and fabric should run on the same NIC. ### Configuration steps In the heartbeat sub-stanza: 1. Set `mode` to `mesh`. 2. (Optional) Set `address` to the IP of the interface intended for intracluster communication. This interface should also be used as the address for the _fabric_ sub-stanza. Needed when isolating intra-cluster traffic from the service traffic. 3. Set [`mesh-seed-address-port`](https://aerospike.com/docs/database/reference/config#network__mesh-seed-address-port) to be the IP address and heartbeat port of a node in the cluster. 4. Set [`interval`](https://aerospike.com/docs/database/reference/config#network__interval) and [`timeout`](https://aerospike.com/docs/database/reference/config#network__timeout) - [`interval`](https://aerospike.com/docs/database/reference/config#network__interval) (recommended: 150) controls how often to send a heartbeat packet. - [`timeout`](https://aerospike.com/docs/database/reference/config#network__timeout) (recommended: 10) controls the number of intervals after which a node is considered to be missing by the rest of the nodes in the cluster if they haven’t received the heartbeat from the missing node. - With the recommended settings, a node will be aware of another node leaving the cluster within 1.5 seconds. ### Example Terminal window ```bash ... heartbeat { mode mesh # Send heartbeats using Mesh (Unicast) protocol address 192.168.1.100 # (Optional) (Default: any) IP of the NIC on # which this node is listening to heartbeat port 3002 # port on which this node is listening to # heartbeat mesh-seed-address-port 192.168.1.100 3002 # IP address for seed node in the cluster # This IP happens to be the local node mesh-seed-address-port 192.168.1.101 3002 # IP address for seed node in the cluster mesh-seed-address-port 192.168.1.102 3002 # IP address for seed node in the cluster mesh-seed-address-port 192.168.1.103 3002 # IP address for seed node in the cluster interval 150 # Number of milliseconds between heartbeats timeout 10 # Number of heartbeat intervals to wait before # timing out a node } ... ``` ### What’s next? - Configure [service, fabric, and admin sub-stanzas](https://aerospike.com/docs/database/manage/network/), which define the interface to use for application-to-node communication. - (Optional) Configure [Rack awareness](https://aerospike.com/docs/database/manage/namespace/rack-aware), which enables support in Aerospike for top-of-rack switch failure. - Learn more about the [Clustering Architecture](https://aerospike.com/docs/database/learn/architecture/clustering).