Applications FAQ

Can I run Casandra inside an Istio mesh?

By default, Cassandra broadcasts the address it uses for binding (accepting connections) to other Cassandra nodes as its address. This is usually the pod IP address and works fine without a service mesh. However, with a service mesh this configuration does not work. Istio and other service meshes require localhost (127.0.0.1) to be the address for binding.

There are two configuration parameters to pay attention to: listen_address and broadcast_address. For running Cassandra in an Istio mesh, the listen_address parameter should be set to 127.0.0.1 and the broadcast_address parameter should be set to the pod IP address.

These configuration parameters are defined in cassandra.yaml in the Cassandra configuration directory (e.g. /etc/cassandra). There are various startup scripts (and yaml files) used for starting Cassandra and care should be given to how these parameters are set by these scripts. For example, some scripts used to configure and start Cassandra use the value of the environment variable CASSANDRA_LISTEN_ADDRESS for setting listen_address.

Can I run Elasticsearch inside an Istio mesh?

There are two Elasticsearch configuration parameters that need to be set appropriately to run Elasticsearch with Istio: network.bind_host and network.publish_host. By default, these parameters are set to the network.host parameter. If network.host is set to 0.0.0.0, Elasticsearch will most likely pick up the pod IP as the publishing address and no further configuration will be needed.

If the default configuration does not work, you can set the network.bind_host to 0.0.0.0 or localhost (127.0.0.1) and network.publish_host to the pod IP. For example:

...
containers:
- name: elasticsearch
  image: docker.elastic.co/elasticsearch/elasticsearch:7.2.0
  env:
    - name: network.bind_host
      value: 127.0.0.1
    - name: network.publish_host
      valueFrom:
        fieldRef:
          fieldPath: status.podIP
   ...

Refer to Network Settings for Elasticsearch for more information.