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What is a Pack?¶
A “pack” is the unit of deployment for integrations and automations that extend EWC. Typically a pack is organized along service or product boundaries e.g. AWS, Docker, Sensu etc. A pack can contain Actions, Workflows, Rules, Sensors, and Aliases. EWC content is always part of a pack, so it’s important to understand how to create packs and work with them.
Some packs extend EWC to integrate it with external systems — like AWS, GitHub, or JIRA. We call them “integration packs”. Some packs capture automation patterns — they contain workflows, rules, and actions for a specific automation process — like the st2 demo pack. We call them “automation packs”. This naming is mostly a convention: EWC itself makes no distinction between the two.
Integration packs can be shared and reused by anyone who uses the service that pack is built for. You can find many examples of these at the StackStorm Exchange. Automation packs are often very site-specific and have little use outside of a particular team or company; they are usually shared internally.
EWC packs are managed through
st2 pack <...> commands:
st2 pack -h will give you a useful
Some (such as the
core pack for basic StackStorm actions) come pre-installed with EWC. All
other packs need to be installed by you. Luckily this is pretty easy!
get are the primary commands to get information about local packs:
# List all installed packs st2 pack list # Get detailed information about an installed pack st2 pack get core
When using EWC and pack management actions, all packs are installed into the system packs
directory, which defaults to
There’s over a hundred StackStorm packs already available to you!
StackStorm Exchange is a collection of ready-made packs
submitted and maintained by the StackStorm community. There are packs for most of the popular
cloud providers and DevOps tools, as well as more peculiar integrations (hello,
You can browse the pack listing at exchange.stackstorm.org,
or search the pack index via CLI with
st2 pack search and
st2 pack show:
# Search query is applied across all pack parameters. # It will search through pack names: st2 pack search sensu # And keywords: st2 pack search monitoring # And description (use quotes for multi-word search): st2 pack search "Amazon Web Services" # And even pack author: st2 pack search "Jon Middleton" # Show an index entry for the pack # with the exact name match st2 pack show sensu
As of EWC v2.4, you can also do this via the Web UI! Explore the new “Packs” tab to see more.
Installing a Pack¶
Installing a pack is simple:
# Install from the Exchange by pack name st2 pack install sensu # You can also install multiple packs: st2 pack install datadog github
This command will download packs from the StackStorm Exchange organization on GitHub, place them under
register them with EWC.
st2 pack install works with git repositories: there is one for every pack in the
Exchange, and you can install your own packs from git just as easily.
# Install your own pack from git st2 pack install https://github.com/emedvedev/chatops_tutorial
By default, the latest commit to a pack repository will be installed, but you can specify a particular version, branch, tag, or even a commit hash. Just use =:
# Fetch a specific commit st2 pack install cloudflare=776b9a4 # Or a version tag st2 pack install cloudflare=0.1.0 # Or a branch st2 pack install https://github.com/emedvedev/chatops_tutorial=testing
Finally, you can install a pack from existing local dir:
# Install a pack from '/home/stanley/bitcoin' dir st2 pack install file:///home/stanley/bitcoin
Installing a pack from a directory that is a git repository will only install the latest commit, and ignores any subsequent uncommitted changes to the files.
st2 pack install on an already installed pack will replace it with the requested
version or upgrade to latest if the version is not specified. Your config file will not be
overwritten, so you can revert to an older version just as easily, but for production deployments
we recommend to always specify versions in case there are major changes in
To uninstall a pack, use
st2 pack remove sensu
Configuring a Pack¶
Integration packs often require configuration for your environment. For example, you need to specify an SMTP server to use the email pack, a puppet master URL to use the Puppet pack, or a Keystone endpoint and tenant credentials for OpenStack.
Most packs that require configuration can be configured interactively:
st2 pack config cloudflare
You will be prompted for configuration parameters in an interactive tool with descriptions,
suggestions, and defaults. You will also be asked to verify your final config file in a text editor
before saving it; it’s optional, and most packs don’t require more than two or three fields, but we
have to comply with Health and Safety. The generated file will be placed in
/opt/stackstorm/configs/<pack>.yaml and loaded.
NB: EWC loads pack configuration into MongoDB. This is automatically loaded when you use
st2 pack config. But if you manually edit your pack configuration, or use configuration
management tools to manage those files, you must tell EWC to load the updated config.
You can do this with:
sudo st2ctl reload --register-configs. Otherwise there will be much
head-scratching as you wonder why EWC seems to be completely ignoring your updated configuration.
Trust us. We’ve all been there.
For more nice tricks on pack configuration, see Pack Configuration.
Developing a Pack¶
See Create and Contribute a Pack for details on how to package your integrations and automations in a pack, how to fork a pack for development or create your own, how to publish it, and how to contribute it to the EWC community. If you’re planning to develop any EWC content, we would strongly suggest getting yourself familiar with that page: every piece of content in StackStorm has to belong to a pack, and a good understanding of pack workflow will make your development process much easier!
Explore existing packs for many common products and tools: StackStorm Exchange.
Learn how to write a pack and contribute to the community - Create and Contribute a Pack.
Check out tutorials on stackstorm.com - a growing set of practical examples of automating with EWC.
For information on pack testing, please see the Pack Testing page.
Under the Hood: Pack Basics¶
st2 pack commands described above are a convenience layer on top of pack basics. Once you
understand the basics, you can work with the pack content directly, which might be preferred if
you work with configuration management or have a very specific deployment workflow.
Packs are placed in the system pack directory - by default
virtualenv needs to be created for each pack containing Python actions/sensors under
/opt/stackstorm/virtualenv. Python dependencies are installed inside the virtualenv with
pip -r requirements.txt. If you use
st2 pack install, this is handled automatically for you.
When EWC loads the content, it looks into the system packs directory (
and any additional directories listed in
(typically in /etc/st2/st2.conf).
The value must be a string of directory paths, separated by a colon (think
$PATH). For example:
Directories are always searched from left to right in the order they are specified, with the system packs directory always searched first.
A pack configuration file must be stored as
/opt/stackstorm/configs/<pack_ref>.yaml and follow
a schema defined in
/opt/stackstorm/packs/<pack_dir>/config.schema.yaml. See the
Pack Configuration section for details.
When the pack content changes, it has to be registered again (reloaded). To register individual
st2 pack register --packs=pack1,pack2. To register everything at once, use
sudo st2ctl reload. Use
-h to explore the fine-tuning flags.
Installing Packs from Private Repositories¶
Access tokens are used with HTTPS URLs, for example:
$ st2 pack install https://<user>:<token>@github.com/username/repo.git
Your token will be logged in EWC, git, your shell history, and probably other log files, including git error logs. Using SSH authentication is usually a better choice.
For SSH (URLs starting with
git@) authentication you have to create a deploy key. Note that pack installation is run as
root by default. EWC will use root’s SSH configuration and private keys. Use
~root/.ssh/config to configure a Git-specific private key if you do not want to use root’s
default private key.
Deploy keys are more secure than personal access tokens and can be configured on a per-repo basis.
Using Python 3 for Pack Python Virtual Environment¶
This functionality is only available in EWC v2.8.0 and above. Some additional fixes and improvements to this functionality were introduced in EWC v3.0.1.
When installing a pack, a Python virtual environment is created using the Python binary defined by
actionrunner.python_binary config option. By default, the same Python 2.7.x binary which is
used by all the EWC components and services is used for pack virtual environments.
If you need to use Python 3 for running your pack Python actions, you can do that by passing the
--python3 flag to the
st2 pack install command (e.g.
st2 pack install libcloud
This will create the pack virtual environment using the Python 3 binary specified by
actionrunner.python3_binary config option. This value defaults to
this to work, Python 3 needs to be installed on your system.
When installing Python 3, default prefix of
/usr/local should be used and base
Python 3 libraries should be installed and available in either
/usr/local/lib/python3.6. If a custom prefix was used when compiling / installing Python 3
./configure --prefix=/opt/lib) you also need to configure
actionrunner.python3_prefix option in
st2.conf to match that value.
Keep in mind that this feature only means Python runner actions will be executed using Python 3 binary. All the EWC components and services, including the action runner will still use Python 2 binary.
If you want all the EWC components and services to also run under Python 3 you should look at the Ubuntu Bionic packages where everything runs under Python 3.6. These are in the “unstable” repositories for 3.0, and will be GA in 3.1. On Ubuntu Bionic only packs which work under Python 3 are supported.
Installing Packs from Behind a Proxy¶
If your network uses a proxy to connect to the Internet, you must configure EWC to use that proxy
for pack installation. This is done by setting the
variables for the
If your proxy is performing SSL MITM,
decryption/encryption, you may need to pass in the path to the proxy CA cert, using the
proxy_ca_bundle_path environment variable.
Proxy Configuration via Environment Variables¶
On Ubuntu systems, edit
/etc/default/st2api to set the
proxy configuration environment variables.
For RHEL/CentOS systems, edit
EWC will use these environment variables for pack installation. The file contents should look as follows:
http_proxy=http://proxy.server.io:port https_proxy=http://proxy.server.io:port no_proxy=localhost,127.0.0.1
For HTTPS proxy with cert specify additional
http_proxy=http://proxy.server.io:port https_proxy=http://proxy.server.io:port proxy_ca_bundle_path=/etc/ssl/certs/proxy-ca.pem no_proxy=localhost,127.0.0.1
After editing these files, restart the
$ sudo st2ctl restart-component st2api $ sudo st2ctl restart-component st2actionrunner
When using HTTPS proxy with CA bundle (MITM), you must make sure the proxy CA bundle is an accepted root CA in your OS. Please refer to your OS instructions to register the proxy CA certificate.
This is required for tools like
curl etc to function with a proxy. Some packs
use those tools under the hood and therefore proxy CA registration step is critical for those
packs to work.
Hosting Your Own Pack Index¶
When you run pack management commands like
st2 pack install sensu or
st2 pack search git,
EWC uses a pack index file to resolve short names and perform searches. A pack index is,
essentially, a JSON object: it contains metadata and URLs for all available packs.
The StackStorm Exchange index file is a default file used by all EWC instances, and a good example of the index format. The file is hosted on GitHub (StackStorm-Exchange/index) and proxied through CloudFlare CDN.
The index path is specified in
content.index_url. You can replace the default
index, or even use more than one with a comma-separated list:
Contents from all specified indexes will merge with descending priority (left to right).
In the example above,
sensu pack in your own index would override
from the Exchange.
There are multiple reasons to consider hosting your own index, especially with HA deployments or multi-server setups:
mirroring: in case the main index is not available, your mirror will be used.
forking: if you fork Exchange packs often, you can create an index that is going to list your forks.
enterprise restrictions: if you need pack names to resolve, but can’t install from github, you can specify your own index as the only source.
a centralized resolver: in a multi-server deployment, you can host an index to keep repo URLs in a centralized location.
bragging rights: get your own packs resolvable by short names because the cool kids are doing it.
In most cases there are many other ways to solve the same problem, but sometimes a pack index
is a viable alternative. Create your index file and make it accessible over HTTPS, change
st2.conf—and you’re good!
To monitor index health, the
/packs/index/health API endpoint will show you the state of all
indexes used by your EWC instance.
Questions? Problems? Suggestions? Engage!