Deployex is a lightweight tool designed for managing deployments in Elixir applications without relying on additional deployment tools like Docker or Kubernetes. Its primary goal is to utilize the mix release package for executing full deployments or hot-upgrades, depending on the package's content, while leveraging OTP distribution for monitoring and data extraction.

Deployex acts as a central deployment runner, gathering crucial deployment data such as the current version and release package contents. The content of the release package enables it to run for a full deployment or a hot-upgrade. Meanwhile, on the development front, your CI/CD pipeline takes charge of crafting and updating packages for the target release. This integration ensures that Deployex is always equipped with the latest packages, ready to facilitate deployments.

Deployex is currently used by Calori Web Server and you can check its deployment.

Upon deployment, the following dashboard becomes available, offering access to logs for both Deployex and monitored applications, along with an IEX terminal."

• Monitors multiple Elixir application instances and automatically restarts them if they crash for any reason.
• Includes a backoff delay restart mechanism to prevent excessive restarts.
• Performs full deployments based solely on the release file generated by mix release.
• Supports hot code reloading for applications using the Jellyfish library.
• Provides rollback functionality if a monitored app version remains unstable after a certain period.
• Rolled-back monitored app versions are ghosted, preventing their redeployment.
• Ensures all instances remain connected to the OTP distribution, including deployex itself.
• Supports OTP distribution with mutual TLS (mTLS) for secure monitoring of apps and deployex.
• Provides the ability to run pre-commans prior deployments for Database migrations or any other eval command.
• Allows access to current log files (stdout and stderr) for both monitored apps and deployex.
• Provides access to the IEx shell for monitored apps and deployex.
• Provides installer script to be used with ubuntu hosts.
• Provides status information per instance:
  • OTP connectivity
  • Version history
  • Last deployment status
  • Number of restarts

• Add telemetry support for deployex to capture metrics and telemetry via OTP distribution.
• Integrate CPU utilization monitoring from the OTP distribution.
• Continuous improvement in UI design.

You can kickstart the setup with the following commands, the default number of replicas is 3:

mix deps.get
iex --sname deployex --cookie cookie -S mix phx.server
[info] Initialising deployment server
[info] Running DeployexWeb.Endpoint with Bandit 1.5.3 at 127.0.0.1:5001 (http)
[info] Access DeployexWeb.Endpoint at http://localhost:5001
[watch] build finished, watching for changes...
Erlang/OTP 26 [erts-14.1.1] [source] [64-bit] [smp:10:10] [ds:10:10:10] [async-threads:1] [jit]

Interactive Elixir (1.16.0) - press Ctrl+C to exit (type h() ENTER for help)

Rebuilding...

Done in 407ms.
[error] Invalid version map at: /tmp/myphoenixapp/versions/myphoenixapp/local/current.json reason: enoent

Now you can visit localhost:5001 from your browser. You should expect the following dashboard:

PS: The error message in the CLI is due to no monitored app is available to be deployed. If you want to proceed for a local test, follow the steps at Running Deployex and Monitored app locally. Also, it is important to note that the distribution will be required so this is the reason to add -sname deployex in the command.

The Deployex app expects a current.json file to be available, which contains version and hash information. This file is mandatory for full deployment and hot upgrades.

Expected location in the release folder:

# production path
s3://{monitored_app}-{env}-distribution/versions/{monitored_app}/{env}/current.json
# local test path
/tmp/{monitored_app}/versions/{monitored_app}/{env}/current.json

Expected Json format for current.json:

{
  "version": "1.0.0",
  "pre_commands": [ "eval MyApp.Migrator.create", "eval MyApp.Migrator.migrate" ], # optional field
  "hash": "local"
}

Once the file is captured, the deployment will start if no app is running or if the current app is running with a version that differs from the current.json file.

Expected location in the release folder:

# production path
s3://{monitored_app}-{env}-distribution/dist/{monitored_app}/{monitored_app}-{version}.tar.gz
# local test path
/tmp/{monitored_app}/dist/{monitored_app}/{monitored_app}-{version}.tar.gz

Deployex application typically requires several environment variables to be defined for proper operation. Ensure that you have the following environment variables set when running in production where the ones that have a default value available are not required:

For local testing, these variables are not expected or set to default values.

If you intend to install Deployex directly on an Ubuntu server, you can utilize the installer script provided in the release package. For an example of monitored app, please see the setup for the Calori Web Server. The installer script requires a JSON configuration file, an example of which can be found here. This JSON file can also export environment variables specific to the monitored applications.

Currently, the release and installation process supports Ubuntu versions 20.04 and 22.04. However, you have the option to manually compile and install Deployex on your target system.

Your application will likely require database commands, such as migrations. Deployex handles these through pre-commands specified in current.json under the pre_commands field. These commands will be executed in the order they are listed, before the application starts. If a pre-command is needed and does not require changes to the application itself, using pre-commands in conjunction with hotupgrade is ideal to avoid unnecessary downtime.

Deployex is currently using AWS secrets to fecth its secrets using config provider. The following secret manager name pattern is expected in AWS (It is important to note that this name is expected to not contain "_"):

deployex-${deployex_monitored_app_name}-${deployex_cloud_environment}-secrets

and the following secrets are expected:

For local testing, the root path used for distribution releases and versions is /tmp/{monitored_app}. Follow these steps:

Create the required release folders:

export monitored_app_name=myphoenixapp
mkdir -p /tmp/${monitored_app_name}/dist/${monitored_app_name}
mkdir -p /tmp/${monitored_app_name}/versions/${monitored_app_name}/local/

It is important to note that for local deployments, deployex will use the path /tmp/deployex for local storage. This means you can delete the entire folder to reset any local version, history, or configurations.

In this example, we create a brand new application using mix phx.new and added the library Jellyfish for testing hotupgrades.

mix local.hex
mix archive.install hex phx_new
mix phx.new myphoenixapp --no-ecto
cd myphoenixapp

vi rel/env.sh.eex
# Add the following lines:

#!/bin/sh
# Set a default Erlang cookie value if not provided by ENV VAR.
# This default is temporary; update it using AWS secrets and config provider.
[ -z ${RELEASE_COOKIE} ] && export RELEASE_COOKIE="cookie"
export RELEASE_DISTRIBUTION=sname
[ -z ${RELEASE_NODE_SUFFIX} ] && export RELEASE_NODE_SUFFIX=""
export RELEASE_NODE=<%= @release.name %>${RELEASE_NODE_SUFFIX}

# save the file :wq

Add Jellyfish library ONLY if the application will need hotupgrades

def deps do
  [
    {:jellyfish, "~> 0.1.2"}
  ]
end

You also need to add the following lines in the mix project

  def project do
    [
      ...
      compilers: Mix.compilers() ++ [:gen_appup, :appup],
      releases: [
        myphoenixapp: [
          steps: [:assemble, &Jellyfish.Releases.Copy.relfile/1, :tar]
        ]
      ],
      ...
    ]
  end

Open the config/prod.exs and replace the static manifest for a live reload

#config :myphoenixapp, MyphoenixappWeb.Endpoint,
#  cache_static_manifest: "priv/static/cache_manifest.json"
# Since the application is using the Hot upgrade, the manifest cannot be static
config :myphoenixapp, MyphoenixappWeb.Endpoint,
live_reload: [
  patterns: [
    ~r"priv/static/.*(js|css|png|jpeg|jpg|gif|svg)$",
    ~r"priv/gettext/.*(po)$"
  ]
]

Then you can compile and generate a release

mix deps.get
MIX_ENV=prod mix assets.deploy
MIX_ENV=prod mix release
...
No appups, nothing to move to the release
* assembling myphoenixapp-0.1.0 on MIX_ENV=prod
* using config/runtime.exs to configure the release at runtime
* hot-upgrade copying release file to /Users/testeves/Workspace/Esl/myphoenixapp/_build/prod/rel/myphoenixapp/releases/myphoenixapp-0.1.0.rel
* building /Users/testeves/Workspace/Esl/myphoenixapp/_build/prod/myphoenixapp-0.1.0.tar.gz

Move the release file to the distributed folder and updated the version:

export app_name=myphoenixapp
cp _build/prod/${app_name}-0.1.0.tar.gz /tmp/${app_name}/dist/${app_name}
echo "{\"version\":\"0.1.0\",\"pre_commands\": [],\"hash\":\"local\"}" | jq > /tmp/${app_name}/versions/${app_name}/local/current.json

Move back to the deployex project and run the command line with the required ENV vars.

NOTE: All env vars that are available for deployex will also be available to the monitored_app

export SECRET_KEY_BASE=e4CXwPpjrAJp9NbRobS8dXmOHfn0EBpFdhZlPmZo1y3N/BzW9Z/k7iP7FjMk+chi
export PHX_SERVER=true
export DATABASE_URL=ecto://postgres:postgres@localhost:5432/myphoenixapp_prod # In case your monitored add is using ecto
iex --sname deployex --cookie cookie -S mix phx.server
...

[info] Update is needed at instance: 1 from: <no current set> to: 0.1.0.
[warning] HOT UPGRADE version NOT DETECTED, full deployment required, result: []
[info] Full deploy instance: 1 deploy_ref: 15014.
[info] Initialising monitor server for instance: 1
[info] Ensure running requested for instance: 1 version: 0.1.0
[info]  # Identified executable: /tmp/deployex/varlib/service/myphoenixapp/1/current/bin/myphoenixapp
[info]  # Starting application
[info]  # Running instance: 1, monitoring pid = #PID<0.768.0>, OS process = 52708 deploy_ref: 15014.
[info]  # Application instance: 1 is running
[info]  # Moving to the next instance: 2
...
iex(deployex@hostname)1>

You should then visit the application and check it is running localhost:5001. Since you are not using mTLS, the dashboard should look like this:

Note that the OTP-Nodes are connected, but the mTLS is not supported. The mTLS can be enabled and it will be covered ahead. Leave this terminal running and open a new one to compile and release the monitored app.

In this scenario, the existing application will undergo termination, paving the way for the deployment of the new one. It's crucial to maintain the continuous operation of Deployex throughout this process. Navigate to the myphoenixapp project and increment the version in the mix.exs file. Typically, during release execution, the CI/CD pipeline either generates the package from scratch or relies on the precompiled version, particularly for hot-upgrades. If you've incorporated the Jellyfish library and wish to exclusively create the full deployment package, for this test you must follow the steps:

1. Remove any previously generated files and generate a new release

cp myphoenixapp
rm -rf _build/prod
MIX_ENV=prod mix assets.deploy
MIX_ENV=prod mix release
...
Generated myphoenixapp app
No appups, nothing to move to the release
Check your digested files at "priv/static"
No appups, nothing to move to the release
* assembling myphoenixapp-0.1.1 on MIX_ENV=prod
* using config/runtime.exs to configure the release at runtime
* hot-upgrade copying release file to /Users/testeves/Workspace/Esl/myphoenixapp/_build/prod/rel/myphoenixapp/releases/myphoenixapp-0.1.1.rel
* building /Users/testeves/Workspace/Esl/myphoenixapp/_build/prod/myphoenixapp-0.1.1.tar.gz

2. Now, keep Deployex running in another terminal and copy the release file to the distribution folder and proceed to update the version accordingly:

export app_name=myphoenixapp
cp _build/prod/${app_name}-0.1.1.tar.gz /tmp/${app_name}/dist/${app_name}
echo "{\"version\":\"0.1.1\",\"pre_commands\": [],\"hash\":\"local\"}" | jq > /tmp/${app_name}/versions/${app_name}/local/current.json

3. You should then see the following messages in the Deployex terminal while updating the app:

[info] Update is needed at instance: 1 from: 0.1.0 to: 0.1.1.
[warning] HOT UPGRADE version NOT DETECTED, full deployment required, result: []
[info] Full deploy instance: 1 deploy_ref: 61157.
[info] Requested instance: 1 to stop application pid: #PID<0.768.0>
[warning] Remaining beam app removed for instance: 1
[info] Initialising monitor server for instance: 1
[info] Ensure running requested for instance: 1 version: 0.1.1
[info]  # Identified executable: /tmp/deployex/varlib/service/myphoenixapp/1/current/bin/myphoenixapp
[info]  # Starting application
[info]  # Running instance: 1, monitoring pid = #PID<0.840.0>, OS process = 53882 deploy_ref: 61157.
[info]  # Application instance: 1 is running
[info]  # Moving to the next instance: 2
...

For this scenario, the project must first be compiled to the current version and subsequently compiled for the version it's expected to update to. The current.json file deployed includes the git hash representing the current application version. In this local testing phase, it suffices to compile for the previous version, such as 0.1.1, and the subsequent version, like 0.1.2, so the necessary files will be automatically populated.

1. Since the application is already compiled for 0.1.1, change the mix.exs to 0.1.2, apply any other changes if you want to test and execute the command:

MIX_ENV=prod mix assets.deploy
MIX_ENV=prod mix release
...
Generated myphoenixapp app
You can find your generated appups in rel/appups/myphoenixapp/ with the .appup extension
Check your digested files at "priv/static"
You can find your generated appups in rel/appups/myphoenixapp/ with the .appup extension
* assembling myphoenixapp-0.1.2 on MIX_ENV=prod
* using config/runtime.exs to configure the release at runtime
* hot-upgrade copying release file to /Users/testeves/Workspace/Esl/myphoenixapp/_build/prod/rel/myphoenixapp/releases/myphoenixapp-0.1.2.rel
* building /Users/testeves/Workspace/Esl/myphoenixapp/_build/prod/myphoenixapp-0.1.2.tar.gz

2. Now, copy the release file to the distribution folder and proceed to update the version accordingly:

export app_name=myphoenixapp
cp _build/prod/${app_name}-0.1.2.tar.gz /tmp/${app_name}/dist/${app_name}
echo "{\"version\":\"0.1.2\",\"pre_commands\": [],\"hash\":\"local\"}" | jq > /tmp/${app_name}/versions/${app_name}/local/current.json

You can then check that deployex had executed a hot upgrade in the application:

[info] Update is needed at instance: 1 from: 0.1.1 to: 0.1.2.
[warning] HOT UPGRADE version DETECTED, from: 0.1.1 to: 0.1.2
[info] Hot upgrade instance: 1 deploy_ref: 61157.
[info] Unpacked successfully: ~c"0.1.2"
[info] Installed Release: ~c"0.1.2"
[info] Made release permanent: 0.1.2
[info] Release upgrade executed with success at instance: 1 from: 0.1.1 to: 0.1.2
[info]  # Moving to the next instance: 2
...

you can check that the version and the deployment status has changed in the dashboard:

In order to improve security, mutual TLS (mTLS for short) can be employed to encrypt communication during OTP distribution. To implement this, follow these steps:

1. Generate the necessary certificates, deployex has a good examples of how to create self-signed tls certificates:

cd deployex
make tls-distribution-certs

2. Copy the generated certificates to the /tmp folder:

cp ca.crt /tmp
cp deployex.crt /tmp
cp deployex.key /tmp

3. Create the inet_tls.conf file with the appropriate paths, utilizing the command found in rel/env.sh.eex:

export DEPLOYEX_OTP_TLS_CERT_PATH=/tmp

test -f /tmp/inet_tls.conf || (umask 277
 cd /tmp
 cat >inet_tls.conf <<EOF
[
  {server, [
    {certfile, "${DEPLOYEX_OTP_TLS_CERT_PATH}/deployex.crt"},
    {keyfile, "${DEPLOYEX_OTP_TLS_CERT_PATH}/deployex.key"},
    {cacertfile, "${DEPLOYEX_OTP_TLS_CERT_PATH}/ca.crt"},
    {verify, verify_peer},
    {secure_renegotiate, true}
  ]},
  {client, [
    {certfile, "${DEPLOYEX_OTP_TLS_CERT_PATH}/deployex.crt"},
    {keyfile, "${DEPLOYEX_OTP_TLS_CERT_PATH}/deployex.key"},
    {cacertfile, "${DEPLOYEX_OTP_TLS_CERT_PATH}/ca.crt"},
    {verify, verify_peer},
    {secure_renegotiate, true},
    {server_name_indication, disable}
  ]}
].
EOF
)

4. Ensure that myphoenixapp also utilizes the same options and certificate by updating rel/env.sh.eex:

cd myphoenixapp
vi rel/env.sh.eex
# Add the following line
#!/bin/sh
export ELIXIR_ERL_OPTIONS="-proto_dist inet_tls -ssl_dist_optfile /tmp/inet_tls.conf"
# save the file :q

5. To enable mTLS for deployex, set the appropriate Erlang options before running the application in the terminal:

ELIXIR_ERL_OPTIONS="-proto_dist inet_tls -ssl_dist_optfile /tmp/inet_tls.conf -setcookie cookie" iex --sname deployex -S mix phx.server

After making these changes, create and publish a new version 0.1.3 for myphoenixapp and run the deployex with the command from item 5. After the deployment, you should see the follwoing dashboard:

ATTENTION: Ensure that the cookie is properly set

# production
tail -f /var/log/deployex/deployex-stdout.log
tail -f /var/log/deployex/deployex-stderr.log
# local test
# not available when running as dev env

export RELEASE_NODE_SUFFIX=""
export RELEASE_COOKIE=cookie
# production
/opt/deployex/bin/deployex remote
# local test
# not available when running as dev env

export instance=1
export monitored_app_name=myphoenixapp
# production
tail -f /var/log/${monitored_app_name}/${monitored_app_name}-${instance}-stdout.log
tail -f /var/log/${monitored_app_name}/${monitored_app_name}-${instance}-stderr.log
# local test
tail -f /tmp/${monitored_app_name}/${monitored_app_name}/${monitored_app_name}-${instance}-stdout.log
tail -f /tmp/${monitored_app_name}/${monitored_app_name}/${monitored_app_name}-${instance}-stderr.log

export instance=1
export monitored_app_name=myphoenixapp
export RELEASE_NODE_SUFFIX=-${instance}
export RELEASE_COOKIE=cookie
# production
/var/lib/deployex/service/${monitored_app_name}/${instance}/current/bin/${monitored_app_name} remote
# local test
/tmp/deployex/varlib/service/${monitored_app_name}/${instance}/current/bin/${monitored_app_name} remote

Deployex operates by monitoring applications and versions using folders and files, treating the monitored app as a service. The deployment process involves several steps to ensure smooth transitions:

1. Download and Unpack the New Version: The new version of the application is downloaded and unpacked into the new service folder, ready for deployment.
2. Check if the release contain a hot-upgrade or full deployment: Deployex will check the release file received and if it is a full deployment, goes to the step 3 .
3. Stop the Current Application: The currently running application instance is stopped to prepare for the new deployment.
4. Delete the Previous Service Folder: The previous service folder, containing the previous version of the application, is deleted to make space for the new version.
5. Move the Current Service: The current service folder, representing the current version of the application, is moved to the previous service folder. Simultaneously, the new service folder is moved to become the new current service folder.
6. Start the Application: Finally, the application is started using the version now residing in the current service folder, ensuring that the latest version is active and operational.

By following this process, Deployex facilitates deployments, ensuring that applications are updated while minimizing downtime.

For the test environment:

/tmp/deployex/varlib/service/${monitored_app}/${instance}/previous/${monitored_app}
/tmp/deployex/varlib/service/${monitored_app}/${instance}/new/${monitored_app}
/tmp/deployex/varlib/service/${monitored_app}/${instance}/current/${monitored_app}

For production environment:

/var/lib/deployex/service/${monitored_app}/${instance}/previous/${monitored_app}
/var/lib/deployex/service/${monitored_app}/${instance}/new/${monitored_app}
/var/lib/deployex/service/${monitored_app}/${instance}/current/${monitored_app}

For this scenario, there will be no moving files/folders since the target is to keep the current service folder updated. The sequence is:

1. Download and Unpack the New Version: The new version of the application is downloaded and unpacked into the new service folder, ready for deployment.
2. Check if the release contain a hot-upgrade or full deployment: Deployex will check the release file received and if it is a hot-upgrade, goes to the step 3 .
3. Execute the Hotupgrade checks and verification Deployex will try to run the hotupgrade sequence and if succeeds, it makes the changes permanent. Inc ase of failure, it tries to execute a full deployment with the same release file.