dokku-letsencrypt (Beta) ¶
dokku-letsencrypt is the official plugin for dokku that gives the ability to automatically retrieve and install TLS certificates from letsencrypt.org. During ACME validation, your app will stay available at any time.
Note: Your app must already be deployed and accessible over the internet (i.e. in the browser) in order to add letsencrypt to your app. Your app just being created is not enough. If you need the application to only be deployed via SSL, add a temporary certificate to your app prior to adding letsencrypt by running
dokku certs:generate <app> DOMAIN to make your app accessible via SSL. This is mostly a optional step as the letsencrypt plugin will upgrade non-SSL apps when successful.
Note: If you want to automatically renew the certificates, please use
dokku letsencrypt:cron-job --add to add an auto-renewal cron-job to the crontab of the
dokku user. This is supported starting from the plugin version 0.8.2 which only works with Dokku 0.5 or later.
Note: By running this plugin, you agree to the Let's Encrypt Subscriber Agreement automatically (because prompting you whether you agree might break running the plugin as part of a cronjob).
Note: If you like Let's Encrypt, please consider donating to Let's Encrypt.
# dokku 0.5+ $ sudo dokku plugin:install https://github.com/dokku/dokku-letsencrypt.git # dokku 0.4 $ sudo dokku plugin:install https://github.com/dokku/dokku-letsencrypt.git --committish dokku-0.4
Upgrading from previous versions ¶
# dokku 0.5+ $ sudo dokku plugin:update letsencrypt # dokku 0.4 $ sudo dokku plugin:update letsencrypt dokku-0.4
$ dokku letsencrypt:help letsencrypt <app> Enable or renew letsencrypt certificate for app letsencrypt:auto-renew Auto-renew all apps secured by letsencrypt if renewal is necessary letsencrypt:auto-renew <app> Auto-renew app if renewal is necessary letsencrypt:cleanup <app> Cleanup stale certificates and configurations letsencrypt:cron-job <--add, --remove> Add or remove an auto-renewal cronjob letsencrypt:ls List letsencrypt-secured apps with certificate expiry letsencrypt:revoke <app> Revoke letsencrypt certificate for app
Obtain a Let's encrypt TLS certificate for app
myapp (you can also run this command to renew the certificate):
$ dokku config:set --no-restart myapp DOKKU_LETSENCRYPT_EMAILfirstname.lastname@example.org -----> Setting config vars DOKKU_LETSENCRYPT_EMAIL: email@example.com $ dokku letsencrypt myapp =====> Let's Encrypt myapp... -----> Updating letsencrypt docker image... latest: Pulling from dokku/letsencrypt Digest: sha256:20f2a619795c1a3252db6508f77d6d3648ad5b336e67caaf801126367dbdfa22 Status: Image is up to date for dokku/letsencrypt:latest done -----> Enabling ACME proxy for myapp... -----> Getting letsencrypt certificate for myapp... - Domain 'myapp.mydomain.com' [ removed various log messages for brevity ] -----> Certificate retrieved successfully. -----> Symlinking let's encrypt certificates -----> Configuring SSL for myapp.mydomain.com...(using /var/lib/dokku/plugins/available/nginx-vhosts/templates/nginx.ssl.conf.template) -----> Creating https nginx.conf -----> Running nginx-pre-reload Reloading nginx -----> Disabling ACME proxy for myapp... done
Once the certificate is installed, you can use the
certs:* built-in commands to edit and query your certificate.
You could also use the following command to set an email address for global. So you don't need to type the email address for different application.
dokku config:set --global DOKKU_LETSENCRYPT_EMAILfirstname.lastname@example.org
dokku-letsencrypt uses the Dokku environment variable manager for all configuration. The important environment variables are:
Variable, Default, Description
--------------------------------, -------------, -------------------------------------------------------------------------
DOKKU_LETSENCRYPT_EMAIL, (none), REQUIRED: E-mail address to use for registering with Let's Encrypt.
DOKKU_LETSENCRYPT_GRACEPERIOD, 30 days, Time in seconds left on a certificate before it should get renewed
DOKKU_LETSENCRYPT_SERVER, default, Which ACME server to use. Can be 'default', 'staging' or a URL
You can set a setting using
dokku config:set --no-restart <myapp> SETTING_NAME=setting_value. When looking for a setting, the plugin will first look if it was defined for the current app and fall back to settings defined by
Redirecting from HTTP to HTTPS ¶
Dokku's default nginx template will automatically redirect HTTP requests to HTTPS when a certificate is present.
You can customize the nginx template if you want different behaviour.
dokku-letsencrypt gets around having to disable your web server using the following workflow:
- Temporarily add a reverse proxy for the
/.well-known/path of your app to
- Run the simp_le Let's Encrypt client in a Docker container binding to
$ACMEPORTto complete the ACME challenge and retrieve the TLS certificates
- Install the TLS certificates
- Remove the reverse proxy and reload nginx
For a more in-depth explanation, see this blog post
Dockerfile Deploys ¶
When securing Dockerfile deploys with dokku-letsencrypt, be aware of the proxy mechanism for dokku 0.6+.
For Dockerfile deploys, by default, dokku will determine which ports a container exposes and proxies all those exposed ports in the Docker container by listening on the same port numbers on the host. This means that both the proxies for HTTP port 80 and HTTPS port 443 to the app's container need to be manually configured using the
dokku proxy:ports-* commands in order for certificate validation and browsing to the app via HTTPS to work.
A full workflow for creating a new Dockerfile deployment with dokku-letsencrypt would be:
- Create a new app
myappin dokku and push to the
email@example.com. This guide assumes that the Docker container will be listening for connections on port 5555 so replace container port numbers accordingly if necessary.
- On the dokku host, use
dokku proxy:ports-add myapp http:80:5555to proxy HTTP port 80 to port 5555 on the Docker image
- On the dokku host, use
dokku letsencrypt myappto retrieve HTTPS certificates.
- On the dokku host, use
dokku proxy:ports-add myapp https:443:5555to proxy HTTPS port 443 to port 5555 on the Docker image
- (optional) On the dokku host, use
dokku proxy:ports-remove myapp http:5555:5555to remove a potential leftover proxy that was automatically configured on first deploy.
After these steps, the output of
dokku proxy:ports myapp should look like this:
-----> Port mappings for myapp -----> scheme host port container port http 80 5555 https 443 5555
Note: Step 2 and step 4 cannot be joined together since a configured HTTPS proxy will include a
ssl_certificate line in the app's nginx config that will cause nginx config validation to fail because no valid HTTPS certificate is available until step 3 is completed.
Dealing with rate limit ¶
Be aware that Let's Encrypt is subject to rate limiting. The limit about the number of certificates you can add on a domain per week is a concern for dokku because of the default domain added to your new applications, named like
dokku-letsencrypt on all your applications would create a certificate for each application subdomain on
As a workaround, if you want to encrypt many applications, make sure to add a proper domain for each one and remove their default domain before running
dokku-letsencrypt. For example, if your dokku domain is
dokku.example.com and you want to encrypt your
dokku domains:add foo foo.com dokku domains:remove foo foo.dokku.example.com dokku letsencrypt foo
While playing around with this plugin, you might want to switch to the let's encrypt staging server by running
dokku config:set --no-restart myapp DOKKU_LETSENCRYPT_SERVER=staging to enjoy much higher rate limits and switching back to the real server by running
dokku config:unset --no-restart myapp DOKKU_LETSENCRYPT_SERVER once you are ready.
Generating a Cert for multiple domains ¶
Your default dokku app is accessible under the root domain too. So if you have an application
00-default that is running under
00-default.mydomain.com it is accessible under
mydomain.com too. Now if you apply letsencrypt for your
00-default application, it is not accessible anymore on
mydomain.com. You can add the root domain to your dokku domains by typing
dokku domains:add 00-default mydomain.com and then
dokku letsencrypt 00-default again.
This plugin is released under the MIT license. See the file LICENSE.