Mirroring with InterSystems IRIS Containers

InterSystems IRIS instances deployed in containers can be configured as mirrors the same way you would configure those deployed from a kit, using the procedures described in Configuring Mirroring. However, there are a few points to bear in mind:

The arbiter configured for the mirror (as strongly recommended by InterSystems) can be deployed from the arbiter image provided by InterSystems, which you can download using the same procedures described for the InterSystems IRIS image. (Note that this is a nonroot image, as described in Security for InterSystems IRIS Containers.) You can also use a noncontainerized InterSystems IRIS instance or an arbiter installed from a kit.
When you deploy the InterSystems IRIS and arbiter containers, you must ensure that you publish the ports used by the mirror members, their ISCAgents, and the arbiter to communicate with each other, as described in Mirror Member Network Addresses.
The ISCAgent on each failover and DR async mirror member must be configured to start automatically before InterSystems IRIS starts. This is the default behavior for InterSystems IRIS images. When running an InterSystems IRIS container, you can use the following iris-main ISCAgent options:
```
--ISCAgent true|false
```
If true, the ISCAgent starts when the container starts on the on the default ISCAgent port, 2188. (This is the default behavior if the option is omitted.) If false, the ISCAgent does not start, and the --ISCAgentPort option is ignored.
```
--ISCAgentPort NNNN 
```
Specifies the port to start the ISCAgent on. (The default, if the option is omitted, is 2188.) This option can be used together with --ISCAgent true. If the value provided isn’t a valid port number (for example, if it is not an integer), or the indicated port is in use, the ISCAgent fails to start.
Be sure to review Mirroring Communication, Sample Mirroring Architecture and Network Configurations, and Locating the Arbiter to Optimize Mirror Availability to ensure that your deployment addresses all of the needed networking considerations.