Configure an Application¶
A Deis application stores config in environment variables.
Configure the Application¶
Use deis config to modify environment variables for a deployed application.
$ deis help config
Valid commands for config:
config:list list environment variables for an app
config:set set environment variables for an app
config:unset unset environment variables for an app
config:pull extract environment variables to .env
config:push set environment variables from .env
Use `deis help [command]` to learn more.
When config is changed, a new release is created and deployed automatically.
You can set multiple environment variables with one deis config:set command,
or with deis config:push and a local .env file.
$ deis config:set FOO=1 BAR=baz && deis config:pull
$ cat .env
FOO=1
BAR=baz
$ echo "TIDE=high" >> .env
$ deis config:push
Creating config... done, v4
=== yuppie-earthman
DEIS_APP: yuppie-earthman
FOO: 1
BAR: baz
TIDE: high
Attach to Backing Services¶
Deis treats backing services like databases, caches and queues as attached resources. Attachments are performed using environment variables.
For example, use deis config to set a DATABASE_URL that attaches
the application to an external PostgreSQL database.
$ deis config:set DATABASE_URL=postgres://user:pass@example.com:5432/db
=== peachy-waxworks
DATABASE_URL: postgres://user:pass@example.com:5432/db
Detachments can be performed with deis config:unset.
Custom Domains¶
You can use deis domains to add or remove custom domains to your application:
$ deis domains:add hello.bacongobbler.com
Adding hello.bacongobbler.com to finest-woodshed... done
Once that’s done, you can go into your DNS registrar and set up a CNAME from the new appname to the old one:
$ dig hello.deisapp.com
[...]
;; ANSWER SECTION:
hello.bacongobbler.com. 1759 IN CNAME finest-woodshed.deisapp.com.
finest-woodshed.deisapp.com. 270 IN A 172.17.8.100
Note
Setting a CNAME for your root domain can cause issues. Setting your @ record to be a CNAME causes all traffic to go to the other domain, including mail and the SOA (“start-of-authority”) records. It is highly recommended that you bind a subdomain to an application, however you can work around this by pointing the @ record to the address of the load balancer (if any).
Custom Health Checks¶
By default, Deis only checks that a container is running. You can add a healthcheck by configuring a URL, initial delay, and timeout value:
$ deis config:set HEALTHCHECK_URL=/200.html
=== peachy-waxworks
HEALTHCHECK_URL: /200.html
$ deis config:set HEALTHCHECK_INITIAL_DELAY=5
=== peachy-waxworks
HEALTHCHECK_INITIAL_DELAY: 5
HEALTHCHECK_URL: /200.html
$ deis config:set HEALTHCHECK_TIMEOUT=5
=== peachy-waxworks
HEALTHCHECK_TIMEOUT: 5
HEALTHCHECK_INITIAL_DELAY: 5
HEALTHCHECK_URL: /200.html
If a new release does not pass the healthcheck, the application will be rolled back to the previous release. Beyond that, if an application container responds to a heartbeat check with a different status than a 200 OK, the Router will mark that container as down and stop sending requests to that container.
Track Changes¶
Each time a build or config change is made to your application, a new Release is created.
Track changes to your application using deis releases.
$ deis releases
=== peachy-waxworks Releases
v4 3 minutes ago gabrtv deployed d3ccc05
v3 1 hour 17 minutes ago gabrtv added DATABASE_URL
v2 6 hours 2 minutes ago gabrtv deployed 7cb3321
v1 6 hours 2 minutes ago gabrtv deployed deis/helloworld
Rollback the Application¶
Use deis rollback to revert to a previous release.
$ deis rollback v2
Rolled back to v2
$ deis releases
=== folksy-offshoot Releases
v5 Just now gabrtv rolled back to v2
v4 4 minutes ago gabrtv deployed d3ccc05
v3 1 hour 18 minutes ago gabrtv added DATABASE_URL
v2 6 hours 2 minutes ago gabrtv deployed 7cb3321
v1 6 hours 3 minutes ago gabrtv deployed deis/helloworld
Note
All releases (including rollbacks) append to the release ledger.