gcloud app deploy does not remove previous versions - node.js

Question

I am running a Node.js app on Google App Engine, using the following command to deploy my code:
gcloud app deploy --stop-previous-version
My desired behavior is for all instances running previous versions to be terminated, but they always seem to stick around. Is there something I'm missing?
I realize they are not receiving traffic, but I am still paying for them and they cause some background telemetry noise. Is there a better way of running this command?
Example output of the gcloud app instances list:
As you can see I have two different versions running.

Answer 1

We accidentally blew through our free Google App Engine credit in less than 30 days because of an errant flexible instance that wasn't cleared by subsequent deployments. When we pinpointed it as the cause it had scaled up to four simultaneous instances that were basically idling away.
tl;dr: Use the --version flag when deploying to specify a version name. An existing instance with the same version will be
replaced then next time you deploy.
That led me down the rabbit hole that is --stop-previous-version. Here's what I've found out so far:
--stop-previous-version doesn't seem to be supported anymore. It's mentioned under Flags on the gcloud app deploy reference page, but if you look at the top of the page where all the flags are listed, it's nowhere to be found.
I tried deploying with that flag set to see what would happen but it seemingly had no effect. A new version was still created, and I still had to go in and manually delete the old instance.
There's an open Github issue on the gcloud-maven-plugin repo that specifically calls this out as an issue with that plugin but the issue has been seemingly ignored.
At this point our best bet at this point is to add --version=staging or whatever to gcloud deploy app. The reference docs for that flag seem to indicate that that it'll replace an existing instance that shares that "version":
--version=VERSION, -v VERSION
The version of the app that will be created or replaced by this deployment. If you do not specify a version, one will be generated for you.
(emphasis mine)
Additionally, Google's own reference documentation on app.yaml (the link's for the Python docs but it's still relevant) specifically calls out the --version flag as the "preferred" way to specify a version when deploying:
The recommended approach is to remove the version element from your app.yaml file and instead, use a command-line flag to specify your version ID

Answer 2

As far as I can tell, for Standard Environment with automatic scaling at least, it is normal for old versions to remain "serving", though they should hopefully have zero instances (even if your scaling configuration specifies a nonzero minimum). At least that's what I've seen. I think (I hope) that those old "serving" instances won't result in any charges, since billing is per instance.
I know most of the above answers are for Flexible Environment, but I thought I'd include this here for people who are wondering.
(And it would be great if someone from Google could confirm.)

Answer 3

I had same problem as OP. Using the flex environment (some of this also applies to standard environment) with Docker (runtime: custom in app.yaml) I've finally solved this! I tried a lot of things and I'm not sure which one fixed it (or whether it was a combination) so I'll list the things I did here, the most likely solutions being listed first.
SOLUTION 1) Ensure that cloud storage deletes old versions
What does cloud storage have to do with anything? (I hear you ask)
Well there's a little tooltip (Google Cloud Platform Web UI (GCP) > App Engine > Versions > Size) that when you hover over it says:
(Google App Engine) Flexible environment code is stored and billed from Google Cloud Storage ... yada yada yada
So based on this info and this answer I visited GCP > Cloud Storage > Browser and found my storage bucket AND a load of other storage buckets I didn't know existed. It turns out that some of the buckets store cached cloud functions code, some store cached docker images and some store other cached code/stuff (you can tell which is which by browsing the buckets).
So I added a deletion policy to all the buckets (except the cloud functions bucket) as follows:
Go to GCP > Cloud Storage > Browser and click the link (for the relevant bucket) in the Lifecycle Rules column > Click ADD A RULE > THEN:
For SELECT ACTION choose "Delete Object" and click continue
For SELECT OBJECT choose "Number of newer versions" and enter 1 in the input
Click CREATE
This will return you to the table view and you should now see the rule in the lifecycle rules column.
REPEAT this process for all relevant buckets (the relevant buckets were described earlier).
THEN delete the contents of the relevant buckets. WARNING: Some buckets warn you NOT to delete the bucket itself, only the contents!
Now re-deploy and your latest version should now get deployed and hopefully you will never have this problem again!
SOLUTION 2) Use deploy flags
I added these flags
gcloud app deploy --quiet --promote --stop-previous-version
This probably doesn't help since these flags seem to be the default but worth adding just in case.
Note that for the standard environment only (I heard on the grapevine) you can also use the --no-cache flag which might help but with flex, this flag caused the deployment to fail (when I tried).
SOLUTION 3)
This probably does not help at all, but I added:
COPY app.yaml .
to the Dockerfile
TIP 1)
This is probably more of a helpful / useful debug approach than a fix.
Visit GCP > App Engine > Versions
This shows all versions of your app (1 per deployment) and it also shows which version each instance is running (instances are configured in app.yaml).
Make sure all instances are running the latest version. This should happen by default. Probably worth deleting old versions.
You can determine your version from the gcloud app deploy logs (at the start of the logs) but it seems that the versions are listed by order of deployment anyway (most recent at top).
TIP 2)
Visit GCP > App Engine > Instances
SSH into an instance. This is just a matter of clicking a few buttons (see screenshot below). Once you have SSH'd in run:
docker exec -it gaeapp /bin/bash
Which will get you into the docker container running your code. Now you can browse around to make sure it has your latest code.
Well I think my answer is long enough now. If this helps, don't thank me, J-ES-US is the one you should thank ;) I belong to Him ^^

Answer 4

Google may have updated their documentation cited in #IAmKale's answer
Note that if the version is running on an instance of an auto-scaled service, using --stop-previous-version will not work and the previous version will continue to run because auto-scaled service instances are always running.
Seems like that flag only works with manually scaled services.

Answer 5

This is a supplementary and optional answer in addition to my other main answer.
I am now, in addition to my other answer, auto incrementing version manually on deploy using a script.
My script contents are below.
Basically, the script auto increments version every time you deploy. I am using node.js so the script uses npm version to bump the version but this line could easily be tweaked to whatever language you use.
The script requires a clean git working directory for deployment.
The script assumes that when the version is bumped, this will result in file changes (e.g. changes to package.json version) that need pushing.
The script essentially tries to find your SSH key and if it finds it then it starts an SSH agent and uses your SSH key to git commit and git push the file changes. Else it just does a git commit without a push.
It then does a deploy using the --version flag ... --version="${deployVer}"
Thought this might help someone, especially since the top answer talks a lot about using the --version flag on a deploy.
#!/usr/bin/env bash
projectName="vehicle-damage-inspector-app-engine"
# Find SSH key
sshFile1=~/.ssh/id_ed25519
sshFile2=~/Desktop/.ssh/id_ed25519
sshFile3=~/.ssh/id_rsa
sshFile4=~/Desktop/.ssh/id_rsa
if [ -f "${sshFile1}" ]; then
sshFile="${sshFile1}"
elif [ -f "${sshFile2}" ]; then
sshFile="${sshFile2}"
elif [ -f "${sshFile3}" ]; then
sshFile="${sshFile3}"
elif [ -f "${sshFile4}" ]; then
sshFile="${sshFile4}"
fi
# If SSH key found then fire up SSH agent
if [ -n "${sshFile}" ]; then
pub=$(cat "${sshFile}.pub")
for i in ${pub}; do email="${i}"; done
name="Auto Deploy ${projectName}"
git config --global user.email "${email}"
git config --global user.name "${name}"
echo "Git SSH key = ${sshFile}"
echo "Git email = ${email}"
echo "Git name = ${name}"
eval "$(ssh-agent -s)"
ssh-add "${sshFile}" &>/dev/null
sshKeyAdded=true
fi
# Bump version and git commit (and git push if SSH key added) and deploy
if [ -z "$(git status --porcelain)" ]; then
echo "Working directory clean"
echo "Bumping patch version"
ver=$(npm version patch --no-git-tag-version)
git add -A
git commit -m "${projectName} version ${ver}"
if [ -n "${sshKeyAdded}" ]; then
echo ">>>>> Bumped patch version to ${ver} with git commit and git push"
git push
else
echo ">>>>> Bumped patch version to ${ver} with git commit only, please git push manually"
fi
deployVer="${ver//"."/"-"}"
gcloud app deploy --quiet --promote --stop-previous-version --version="${deployVer}"
else
echo "Working directory unclean, please commit changes"
fi
For node.js users if you call the script deploy.sh you should add:
"deploy": "sh deploy.sh"
In your package.json scripts and deploy with npm run deploy