Asking in #containers-beta will give you better answers on how to clean up resources created for con
Asking in #containers-beta will give you better answers on how to clean up resources created for containers.
Pactually no one from Cloudflare answers anything there, I've been trying for a few days now. This is how I've started venturing into these other places
LI doubt the DOs hold any image space. Check out the wrangler commands if you want to delete images: https://developers.cloudflare.com/workers/wrangler/commands/#containers
PSorry I meant to say "instance", not "image"... every container execution loads an image into an instance. When the instance is finished, it just sits around. That is the thing I'm trying to clean up and I think it's the thing associated with a DO.
LI still don't understand why you want to clean it up? If you don't use it, it will disappear, isn't it? I haven't followed much on containers but it seems weird to me that you want to delete a DO to cleanup some container image space.
PIn this particular use case, it's kind of a security best practice, these are ephermal github runners, so they run once and they should be completeley deleted after
LThe DO instance itself doesn't have the image in its storage, the image is loaded elsewhere and the DO is just a coordinator for the container.
Pya that's what I was afraid of, I have read the actual region (datacenter) a container instance runs is not necessarily the same as the DO, which leads me to believe the DO storage clearing, might NOT actually delete the container instance
1Are you not able to spin up more instances? When a container is shown as inactive in the dash I dont think it actually exists anymore, and should disappear on its own eventually
PI'm seeing them just stick around, for 4 days now, have't tested any longer.
1Yeah they dont still exist, they arent taking up any space. I think youre stressing over nothing
PWell if you are building a real SaaS, and making claims about the way ephemeral compute environments actually dispose of data after use, you want to be 100% sure
PThe State = Inactive actually leads me to belive these instance could actually be re-hydrated, so their state must still exist
1Because you can reboot them from scratch
1Here's some docs on this topic: https://developers.cloudflare.com/containers/platform-details/architecture/#container-shutdown
POk, so it's not like "paused" where the container instance is somehow frozen
1No it delete
POk thanks @1984 Ford Laser for the clarification. I just wanted to make sure I wasn't going to rack petabytes of frozen container instances just waiting to be re-hydrated. But sounds like that is not how it works, anything in a State of Inactive is actually just totally deleted.
1You can track your active usage in the Metrics tab of the container dash
PYes the usage shows what I expect, just paying for the execution time. I just want to be 100% sure I know how the data is handled for these ephemeral github runner use cases, so I can explain it to others. I can imagine this could be a security question in a architecture review/deep dive
PHey @Gabi | Containers and team - follow-up from my ephemeral GitHub runners discussion.
Confirmed Understanding:
Container disk is ephemeral and deleted on stop (thanks for clarifying!)
Only paying for active execution time
Inactive containers don't consume storage
Remaining Question:
While the container instances clean up properly, the Durable Object instances themselves accumulate in the namespace indefinitely.
Current Pattern:
Confirmed Understanding:
Container disk is ephemeral and deleted on stop (thanks for clarifying!) Only paying for active execution time Inactive containers don't consume storageRemaining Question:
While the container instances clean up properly, the Durable Object instances themselves accumulate in the namespace indefinitely.
Current Pattern:
- Each job: → unique DO created
- Container runs → stops → DO hibernates (but persists)
- At 1000 jobs/day → 30K DOs/month → 365K DOs/year**Dashboard shows all these inactive DOs forever** (see screenshot from last week).**Questions:**
- Is this accumulation pattern expected/acceptable for ephemeral workloads?
- Do hibernated DOs (with empty storage via deleteAll()) have any cost or limits?
- Should I implement DO pooling to reuse ~100 DOs across all jobs?
- Or just call storage.deleteAll() + deleteAlarm() in onStop() and not worry about it?For context: GitHub Actions runners are true ephemeral workloads - each job should leave zero trace. Want to ensure I'm architecting this correctly for production SaaS.Current scale: 10 concurrent, but could scale up to 100-500 as usage grows.Thanks!
LDo hibernated DOs (with empty storage via deleteAll()) have any cost or limits?No.
You cannot remove DOs from the namespace list at the moment. It's not a containers thing, it's a DOs thing.
1Are you storing anything in the DO storage currently? If you dont utilise storage in any way currently then they wont incur any storage costs at all
PI don't think so but all of this is kind of magical so I don't actually always know what's happening behind the scenes, like are the container logs being stored as part of the DO storage? I don't know.
I'm coming form a cloud background, where I've seen lots of users get burnned becuase of massive CloudWatch logs bills for example.
I'm coming form a cloud background, where I've seen lots of users get burnned becuase of massive CloudWatch logs bills for example.
1Cloudflare products and the runtime definitely feel like magic sometimes. Logs don't cost anything to just have them emitted, there are products like Workers Analytics Engine or Logpush that do cost money, but simply having them be logged and viewing them live is free
PWill I run into scalability issues, like just paging or searching my DO's if I have potentially millions of them? If they are basically ALL not used, it just seems wasteful. This is why I was thinking I might want to implement so kind of Pooling scheme, where I have a fixed number of DOs that get reused to spin up new container instances, this way I only ever have like 100 DOs.
1Yeah I wouldn't ever worry about having too many instances, especially if you aren't using any storage in them. There isn't any account limits to the number of DO instances you spin up, and theoretically you can scale up millions instantly. There's some mental blocks to jump over with DOs, I would focus on building before worrying about runtime stuff that basically isn't an issue
LI think there is a small mental model mismatch going on here. I never get the full list of DOs and walk it for just the reason you mention. Rather, the way I think everyone does it, is we keep a list of active ones somewhere else. This can either be a stringified version of the uniqueId, or more commonly, folks use getByName or the two-step equivalent of that (get the id by name, then get the stub from that id). The "name" is something we already use for other purposes in most cases. For instance, I use Stytch which creates a unique id for each organization in our SaaS product. That's the "name" I use for my OrgDO. How does that sit with you?
PThanks Larry, this is inline with my understanding of best practices, thinking critically about the "partitioning" strategy for DO, basically how you uniquely name DOs. For named/identified things like organizations, users, cities, etc. this is perfect. The thing I'm struggling with is best practice for using DO's with single use identifiers (like a job run id). I think I just need to accept there will be lots of DO's lingering around forever or use a pool of 100x DOs like "runner-001", "runner-002", etc. and then just reuse those, so my OCD isn't triggered 
- My spider sense is telling me be careful about letting millions of resources just pile up, it could come back to bite you - but I get lots of feedback on this forum saying "don't worry about it"
POr maybe I need to think more about the partition key that actually might make sense for this use case, the account and repo and workflow name for example could be concatenated to create a unique slot. I could either use that or a hash of that to create a unique identifier. - this is probably the way...
LI think you are aligned now. Just keep in mind that you'll have to keep that list of active ones somewhere. When you think one should go away forever, just make absolutely sure it's empty of data. Then delete that key from your outside maintained list. You could have a cron job somewhere that use the Cloudflare API to get the full list and crawl it to check that they are absolutely empty. That's not as trivial as it should be because there are some edge cases. I don't have them in my head but I bet someone else in this conversation does.
HHey, did you mean that a value in globalThis will be the same if the DO instances are running in the same isolate?
LExactly. Surprising but true. I used a Set of instance ids for my experiments. It was not unheard of but it was rare-ish for there to be two. I don't think I ever saw three. I stopped monitoring years ago because I stopped pre-loading stuff into instance variables and I now retrieve from storage just what I needed to handle that one Request/Message. It sounds inefficient, but it's not with an embedded database that has a cache... and it's more memory efficient. It's also cost effective because reads are dirt cheap.
HAmazing, thanks for explaining, we just added an id/counter to prod and hopefully it will shed light on our problem haha
LIs the DurableObject base class in a repo somewhere that can look at?
1Poking around a bit, maybe this is of use? https://github.com/cloudflare/workerd/blob/aee8c81a780095b66f80c424545eb5a97a062452/src/workerd/api/workers-module.h#L43
LThanks. I don't know C++ but this is the "interface" essentially. The "implementation" was in a link on the side of the page you took me to so thanks again. It looks like all it does it set and but there is some other C++ foo I don't follow if anyone knows?
1I found other references to DurableObjectBranded that might also be of use
LI think the implementation is here: https://github.com/cloudflare/workerd/blob/main/src/workerd/api/workers-module.c%2B%2B#L25. It's a c++ file and it does what I said. I'm guessing the other c++ foo is just allocating memory and housekeeping. I think I have what I need. Thanks again for the help.
GitHub
The JavaScript / Wasm runtime that powers Cloudflare Workers - cloudflare/workerd
Jrecent message from over in the d1 channel that might be of interest to folks here eagerly awaiting DO storage read replication...
d1-database
d1-database
Nhow much slower is it to use sql reads directly instead of keeping an in memory
Obviously in memory is going to be effectively instant but it's already a hassle to update data in both sql and in memory.
MapObviously in memory is going to be effectively instant but it's already a hassle to update data in both sql and in memory.
LIf you use SQLite DOs there is already an in-memory cache of your reads, so the difference should be negligible. Using in-memory state could make sense within the context of a single request but otherwise it should be fast enough.
LI switched away from keeping instance variables (with a rare exception) a year or so ago and it was one of my best design decisions. We noticed no bump in cost because reads are so cheap and as you pointed out, you already need to do the writes. We noticed no performance penalty. We didn't know how to measure it but we suspect that cold starts got faster by a few ms, although we now believe that's driven by the size of the SQLite storage.
AHas there been any discussion/consideration around adding some built in lifecycle hooks to Durable Objects? For example, these two would be super helpful:
async onWake() - called automatically after a DO is instantiated
async onEvict() - called automatically right before a DO is evicted
My current pattern is to call onWake() myself, but every time the DO is accessed, and it has a flag internally to check if it's already awake. Works, but annoying ergonomics.
For evict, this is trickier, I currently do not know how to catch this. Having this OOTB would allow us to keep DB connections open between multiple requests while the DO is active and serving. Right now, I have to open and close a pg connection for each request which isn't ideal.
I suppose I could use a setTimeout and close when that expires, and reset the timeon on each new request... but that also feels weird.
How are people solving this pattern?
async onWake() - called automatically after a DO is instantiated
async onEvict() - called automatically right before a DO is evicted
My current pattern is to call onWake() myself, but every time the DO is accessed, and it has a flag internally to check if it's already awake. Works, but annoying ergonomics.
For evict, this is trickier, I currently do not know how to catch this. Having this OOTB would allow us to keep DB connections open between multiple requests while the DO is active and serving. Right now, I have to open and close a pg connection for each request which isn't ideal.
I suppose I could use a setTimeout and close when that expires, and reset the timeon on each new request... but that also feels weird.
How are people solving this pattern?
AThe big problem with that is doing any sort of async work in the constructor, like initializing state with same data from a postgres call
Ain a constructor?