Docker images layers not optimal

[Oleksii-Terekhov]

When I pull/push gcr.io/agones-images/agones-sdk:0.7.0 and gcr.io/agones-images/agones-controller:0.7.0 to private registry, I notice strange layers sizes. After digging in docker history --no-trunc i discover:

$ docker history gcr.io/agones-images/agones-sdk:0.7.0 --no-trunc
SIZE       CREATED BY                                                                                                                 
           ...
36.3MB     /bin/sh -c chown -R agones /home/agones &&     chmod o+x /home/agones/sdk-server                                           
36.3MB     /bin/sh -c #(nop) COPY file:8722bd89cce1b48c82a0c1fd092dc023d376a017c441e11339f5febcb59db882 in /home/agones/sdk-server    
           ...
           
           $ docker history gcr.io/agones-images/agones-controller:0.7.0 --no-trunc
SIZE       CREATED BY                                                                                                                 
           ...
38.1MB     /bin/sh -c chown -R agones /home/agones &&     chmod o+x /home/agones/controller                                           
38.1MB     /bin/sh -c #(nop) COPY file:d96d94ca03fbe2e312ab882c2cf14cee205dad4720f27dc5c1a567cdc6307899 in /home/agones/controller    
...

All binary layers doubled :(

Maybe use COPY --chown=user:group src... dest and fix execution flag via Makefile?

Same thing with gcr.io/agones-images/agones-ping:0.7.0

[cyriltovena]

I'll have a look at this.

[aLekSer]

Actually we can reduce the size of containers twice (same applies to agones-controller image 44.5 vs 82.8 MB):

docker image ls | grep ping 
gcr.io/agones-alexander/agones-ping            0.8.0-86b1326       c0044f50ca15        22 minutes ago      18.9MB
gcr.io/agones-images/agones-ping               0.8.0-86b1326       b66ae871dcec        About an hour ago   31.6MB

I have performed a test with COPY --chmod parameter in Dockerfile and without:
The resulting permissions are the same so it seems that chmod o+x is redundant.
With following lines in Ping Dockerfile:

COPY --chown=agones:root ./bin/ping /home/agones/ping

USER agones

RUN ls -al /home/agones

I got such output:

Step 5/6 : RUN ls -al /home/agones
 ---> Running in 37df117b94c0                                                                                                                                                                            
total 12404
drwxr-sr-x    1 agones   agones        4096 Jan  9 13:06 .
drwxr-xr-x    1 root     root          4096 Dec  4 08:46 ..
-rwxr-xr-x    1 agones   root      12692425 Jan  9 13:06 ping

I got same permissions to a file and directory as when I run current version of Docker image:

docker run --name ping -d gcr.io/agones-images/agones-ping:0.8.0-86b1326  
docker exec -it ping /bin/sh
/ $ ls -al /home/agones
total 12408
drwxr-sr-x    1 agones   agones        4096 Jan  9 12:52 .
drwxr-xr-x    1 root     root          4096 Dec  4 08:46 ..
-rwxr-xr-x    1 agones   root      12692425 Jan  9 12:39 ping

Not sure would the resulting Dockerfile be cross-platform or not.

[cyriltovena]

yep getting the same result on macos, I'm pushing a PR.