Import of core OSM charm layers

[osm/SO.git] / charms / layers / sshproxy / README.md

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+# Overview
+
+This is a [Juju] layer intended to ease the development of charms that need
+to execute commands over SSH, such as proxy charms.
+
+# What is a proxy charm?
+
+A proxy charm is a limited type of charm that does not interact with software running on the same host, such as controlling and configuring a remote device (a static VM image, a router/switch, etc.). It cannot take advantage of some of Juju's key features, such as [scaling], [relations], and [leadership].
+
+Proxy charms are primarily a stop-gap, intended to prototype quickly, with the end goal being to develop it into a full-featured charm, which installs and executes code on the same machine as the charm is running.
+
+# Integration
+
+After you've [created your charm], open `interfaces.yaml` and add
+`layer:sshproxy` to the includes stanza, as shown below:
+```
+includes: ['layer:basic', 'layer:sshproxy']
+```
+
+## Reactive states
+
+This layer will set the following states:
+
+- `sshproxy.configured` This state is set when SSH credentials have been supplied to the charm.
+
+
+## Example
+In `reactive/mycharm.py`, you can add logic to execute commands over SSH. This
+example is run via a `start` action, and starts a service running on a remote
+host.
+```
+...
+import charms.sshproxy
+
+
+@when('sshproxy.configured')
+@when('actions.start')
+def start():
+    """ Execute's the command, via the start action` using the
+    configured SSH credentials
+    """
+    sshproxy.ssh("service myservice start")
+
+```
+
+## Actions
+This layer includes a built-in `run` action useful for debugging or running arbitrary commands:
+
+```
+$ juju run-action mycharm/0 run command=hostname
+Action queued with id: 014b72f3-bc02-4ecb-8d38-72bce03bbb63
+
+$ juju show-action-output 014b72f3-bc02-4ecb-8d38-72bce03bbb63
+results:
+  output: juju-66a5f3-11
+status: completed
+timing:
+  completed: 2016-10-27 19:53:49 +0000 UTC
+  enqueued: 2016-10-27 19:53:44 +0000 UTC
+  started: 2016-10-27 19:53:48 +0000 UTC
+
+```
+## Known Limitations and Issues
+
+### Security issues
+
+- Password and key-based authentications are supported, with the caveat that
+both (password and private key) are stored plaintext within the Juju controller.
+
+# Configuration and Usage
+
+This layer adds the following configuration options:
+- ssh-hostname
+- ssh-username
+- ssh-password
+- ssh-private-key
+
+Once  [configure] those values at any time. Once they are set, the `sshproxy.configured` state flag will be toggled:
+
+```
+juju deploy mycharm ssh-hostname=10.10.10.10 ssh-username=ubuntu ssh-password=yourpassword
+```
+or
+```
+juju deploy mycharm ssh-hostname=10.10.10.10 ssh-username=ubuntu ssh-private-key="`cat ~/.ssh/id_rsa`"
+```
+
+
+# Contact Information
+Homepage: https://github.com/AdamIsrael/layer-sshproxy
+
+[Juju]: https://jujucharms.com/about
+[configure]: https://jujucharms.com/docs/2.0/charms-config
+[scaling]: https://jujucharms.com/docs/2.0/charms-scaling
+[relations]: https://jujucharms.com/docs/2.0/charms-relations
+[leadership]: https://jujucharms.com/docs/2.0/developer-leadership
+[created your charm]: https://jujucharms.com/docs/2.0/developer-getting-started