cdkd
Image overrides for local ECS services
--image-override is a flag of
cdkd local start-service and
cdkd local start-alb. It builds a service's image from
a local Dockerfile, in place of the image the service names.
You need it when the service uses an image that is already in a registry
(ContainerImage.fromEcrRepository or fromRegistry). cdkd pulls that image,
so edits to your working copy would never reach the container, and --watch
has nothing to rebuild for that service.
Combine it with --from-cfn-stack or --from-state to run your working copy
against the deployed stack's real configuration:
cdkd local start-service MyStack/Orders --from-cfn-stack \
--image-override MyStack/Orders=./orders/Dockerfile
The two forms of --image-override
The flag takes a Dockerfile for one named service, or a Dockerfile alone:
| Form | Effect |
|---|---|
--image-override <service>=<dockerfile> |
Uses that Dockerfile for that service. |
--image-override <dockerfile> |
Asks which services should use it. |
The second form opens a picker over the services that have no override yet, so one Dockerfile can serve several services. Naming the same service twice in the first form is an error.
Build arguments, secrets and stages
Three flags pass options to the override builds. Each takes a value for every build or a value for one service, and the value for one service wins.
| Flag | For every build | For one service |
|---|---|---|
--image-build-arg |
KEY=VAL |
<service>:KEY=VAL |
--image-build-secret |
id=src |
<service>:id=src |
--image-target |
<stage> |
<service>=<stage> |
--image-build-secret supplies the file that a Dockerfile line such as
RUN --mount=type=secret,id=<id> reads, which is how a build reaches a
private registry or uses an npm token. cdkd resolves a relative src against
the working directory and expands ~.
Services left without an override
At startup, cdkd warns about each service that still uses an image from a registry. In a terminal it also asks for a Dockerfile for each one. Two flags change this:
--no-interactive-overridesturns the questions off, for scripts and CI.--strict-overridesmakes cdkd refuse to start while any such service remains.
Related
cdkd local start-service: the command these flags belong tocdkd local start-alb: accepts the same flags for the services behind a load balancer