Application SSH Overview
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This topic introduces SSH configuration for applications in your Elastic Runtime deployment.
If you need to troubleshoot an instance of an app, you can gain SSH access to the app using the SSH proxy and daemon.
For example, one of your app instances may be unresponsive, or the log output from the app may be inconsistent or incomplete. You can SSH into the individual VM that runs the problem instance to troubleshoot.
Operators, space managers, and space developers can configure SSH access for Elastic Runtime, spaces, and apps as described in this table:
|User Role||Scope of SSH Permissions Control||How They Define SSH Permissions|
|Operator||Entire deployment||Configure the deployment to allow or prohibit SSH access (one-time). For more information, see Configuring SSH Access for PCF.|
|Space Manager||Space||cf CLI allow-space-ssh and disallow-space-ssh commands|
|Space Developer||Application||cf CLI enable-ssh and disable-ssh commands|
An application is SSH-accessible only if operators, space managers, and space developers all grant SSH access at their respective levels. For example, the image below shows a deployment where:
- An operator allowed SSH access at the deployment level.
- A space manager allowed SSH access for applications running in spaces “A” and “B” but not “C.”
- A space developer enabled SSH access for applications that include “Foo,” “Bar,” and “Baz.”
As a result, apps “Foo,” “Bar,” and “Baz” accept SSH requests.
Space managers and space developers can configure SSH access from the command line. The cf CLI also includes commands to return the value of the SSH access setting. See the Accessing Apps with Diego SSH topic to use and configure SSH at both the application level and the space level.
Pivotal Cloud Foundry deployments control SSH access to apps at the Elastic Runtime level. Additionally, Cloud Foundry supports load balancing of SSH sessions with your load balancer. The Configuring SSH Access topic describes how to set SSH access for your deployment.
The SSH system components include the SSH proxy and daemon, and the system also supports authentication, and load balancing of incoming SSH traffic. The Understanding SSH topic provides a conceptual overview.