Because a container packages only the elements needed to run a containerized application and executes the application natively, it provides standard, well-understood application configuration, behavior, and access. If you are experienced with InterSystems IRIS running on Linux, it doesn’t matter what physical, virtual, or cloud system and distribution your Linux-based InterSystems IRIS container is running on; you interact with it in the same way regardless, just as you would with traditional InterSystems IRIS instances running on different Linux systems.
For detailed information about deploying and using InterSystems IRIS in containers, see Using InterSystems IRIS Containers. Some notable features of containerized InterSystems IRIS are briefly described in the following:
-
InterSystems-provided images — A container image is the executable package, while a container is a runtime instance of an image. InterSystems provides a range of images containing a fully-installed instance of InterSystems IRIS, as described in Using InterSystems IRIS Images; this includes images for InterSystems IRIS with IntegratedML and InterSystems IRIS for Health, as well as free Community Edition Opens in a new tabinstances. You can also use an InterSystems IRIS image from InterSystems as the basis for an image containing your InterSystems IRIS-based application; for more information, see Creating InterSystems IRIS Images.
-
Secure containers — All InterSystems IRIS images contain a nonrootOpens in a new tab instance, which means that it was installed by user irisowner, which does not have root privileges and holds all ownership; nothing is therefore owned by root, or owned or run as any user but irisowner. When deploying InterSystems IRIS under the strictest security, you can use a locked down image to deploy a containerized instance that in addition to being nonroot was installed with Locked Down securityOpens in a new tab. For more information, see Security for InterSystems IRIS Containers.
-
The iris-main program — The iris-main program enables InterSystems IRIS and other products to satisfy the requirements of applications running in containers. The entrypoint application, the main process started when a container is started, is required to block (that is, wait) until its work is complete, but the command starting InterSystems IRIS does not run as a blocking process. The iris-main program solves this by starting InterSystems IRIS and then continuing to run as the blocking entrypoint application. The program also offers a number of options to help tailor the behavior of InterSystems IRIS within a container. For more information about iris-main, see The iris-main Program.
-
The durable %SYS feature — Because a containerized application is isolated from the host environment, it does not write persistent data; whatever it writes inside the container is lost when the container is removed and replaced by a new container. Therefore, an important aspect of containerized application deployment is arranging for data to be stored outside of the container and made available to other and future containers.
The durable %SYS features enables persistent storage of instance-specific data — such as user definitions, audit records, and the log, journal, and WIJ files — when InterSystems IRIS is run in a container, allowing a single instance to run sequentially in multiple containers over time. For example, if you run an InterSystems IRIS container using durable %SYS, you can upgrade the instance by stopping the original container and running a new one that uses the instance-specific data created by the old one. For information about upgrading, see Upgrading InterSystems IRIS Containers; for detailed information on durable %SYS, see Durable %SYS for Persistent Instance Data.
-
Container image catalog — In addition to InterSystems IRIS images, InterSystems provides the following associated images:
-
webgateway — Deploys both the InterSystems Web Gateway and a web server, providing a web server component for containerized deployments of InterSystems IRIS-based applications; for more information, see Web Access Using the Web Gateway Container.
-
arbiter — Deploys an arbiter node as part of mirrored deployments; for more information, see Mirroring with InterSystems IRIS Containers.
-
iris-operator — Deploys the InterSystems Kubernetes OperatorOpens in a new tab (IKO), which extends the open-source Kubernetes container orchestration engine with a custom resourceOpens in a new tab called IrisCluster, representing an InterSystems IRIS sharded cluster, distributed cache cluster, or standalone instance.
-
iam — Deploys InterSystems API ManagerOpens in a new tab (IAM).
-
sam — Deploys InterSystems System Alerting and MonitoringOpens in a new tab (SAM).
-
iscreports_server — Deploys InterSystems Reports ServerOpens in a new tab.
-
passwordhash — Converts a plain-text password to the hashed version, with salt, required to use the InterSystems IRIS PasswordHash configuration parameter; for more information, see Authentication and Passwords.
For a description of the InterSystems Container Registry and information about listing and downloading the images it contains, see Using the InterSystems Container RegistryOpens in a new tab.
