kube-controller-manager has the following property
-deployment-controller-sync-period duration Default: 30s
Period for syncing the deployments.
What does this actually control and what does period for syncing the deployments mean?
Haha most curious thing. You'd expect it does something like controlling how often the controller checks whether the status of Deployment objects are compatible with spec or if there is a change needed.
However currently the controller-manager is notified on changes by the apiserver so it always inherently knows this information already.
There is Issue #71510 where someone points out that parameter seems to be unused. I've done my own search for the parameter and a related search for the variable. As far as I can tell all of these uses are for copying this value around, conversions, declarations, etc, and none of them actually use it for anything at all.
A good test would be setting it to a year and see what happens. I haven't done that though.
Related
According to the docs there is no reference of check panicking in any situation, but I would like to know if there is any edge case where this method could panic rather than returning false.
AFAICS, there are currently two cases where check() may fail:
The path leads to a cycle (see https://github.com/onflow/cadence/issues/2264)
Not sure: The code/type of the stored value is broken and cannot be loaded
Please feel free to open an issue in the Cadence repository if you think this should be changed, and especially why. Thanks!
What is purpose of pod-infra-container-image in kubernetes?
Official documentation says only:
The image whose network/ipc namespaces containers in each pod will use. (default "gcr.io/google_containers/pause-amd64:3.0")
but I don't understand exactly what it does and how it works in detail.
The pause container, which image the --pod-infra-container flag selects, is used so that multiple containers can be launched in a pod, while sharing resources. It mostly does nothing, and unless you have a very good reason to replace it with something custom, you shouldn't. It mostly invokes the pause system call (hence its name) but it also performs the important function of having PID 1 and making sure no zombie processes are kept around.
An extremely complete article on the subject can be found here, from where I also shamelessly stole the following picture which illustrates where the pause container lives:
The pause container is built from https://github.com/kubernetes/kubernetes/tree/master/build/pause . The process itself does nothing so you can replace it with another container of your choice that equally does nothing (with the --pod-infra-container-image parameter of kubelet).
This container is started as a part of each and every pod. Kubernetes is using this well-known, never falling container to setup the network namespace for the pod and make sure the namespace is never empty (all the other containers in the pod might fail). But again, the container process itself does nothing, it's just a placeholder.
Given a node id or matcher, is there a way to determine what state files will be pushed on a state.highstate - without actually running them? i.e. like a dry run.
I have a lot of templating going on in my state files and would like to see what would actually be affected before committing to a run.
You can see what states are being applied by top to a given set of servers with salt $MATCHER state.show_top.
You can do a dry run with salt $MATCHER state.highstate test=True (case sensitive). I don't entirely trust it; sometimes it claims something should get changed, but when I run a real highstate, it turns up clean. I have never had the opposite occur, thankfully.
I have a cluster of 10 memcaches, using consistent hashing. When the key passed to memcached_get() is searched on the unavailable server I get just MEMCACHED_SERVER_MARKED_DEAD response (return value).
I would expect the key should be redistributed to the next available server in this case and I should get NOTFOUND from the next memcached_get() call. However I'm still getting MEMCACHED_SERVER_MARKED_DEAD and so I'm unable to set a new value.
I discovered I can call memcached_behavior_set(..., MEMCACHED_BEHAVIOR_DISTRIBUTION). This causes hash redistribution and it works as I wish then. However, I do not think it is a good approach. Is it?
Generally you want to enable MEMCACHED_BEHAVIOR_DISTRIBUTION from the start if you are dealing with multiple memcached pools. So yes that solution will work.
If you are having further problems, take a look at MEMCACHED_BEHAVIOR_REMOVE_FAILED_SERVERS that will auto purge failed servers from pool after x number of failures.
I found the answer myself.
https://bugs.launchpad.net/libmemcached/+bug/777672
Applying the patch solved all my problems. Note, I wonder it has beed broken since 0.39 and nobody has cared.
I'm a newbie to WF and rather lost. Here's what I have so far:
I've created a workflow service app (xamlx), added needed variables
I've created a custom NativeActivity where I'm calling CreateBookmark from within Execute, which is between the Receive & Send activity for the service. (Ultimately this will actually do something besides creating the bookmark).
The bookmark gets created just fine, but after stepping out of the Execute method, nothing happens for one minute until the service times out, giving me that message "The request channel timed out while waiting for a reply after 00:00:59.9699970. Increase the timeout value passed to the call to Request or increase the SendTimeout value on the Binding. The time allotted to this operation may have been a portion of a longer timeout." (I tried posting an image of the xamlx, but as a newbie it won't let me; suffice it to say I'm getting from my Receive, into my custom native activity, but never getting as far as the SendReply).
I assume I'm missing something rather fundatmental, but I can't see what. I've originally tried using NativeActivity<T> to return what I want, but that behaves the same.
Found out what I was doing wrong: needed to use overload of CreateBookmark that has BookmarkOptions parameter and set it to BookmarkOptions.NonBlocking.
Strangely, I did not find one example anywhere that mentioned this.