I'm trying to run this Zookeeper Openshift example or the equivalent kubernetes one, but I end with errors such as:
FirstSeen LastSeen Count From SubObjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
1h 12s 281 {default-scheduler } Warning FailedScheduling [SchedulerPredicates failed due to PersistentVolumeClaim is not bound: "datadir-zoo-0", which is unexpected., SchedulerPredicates failed due to PersistentVolumeClaim is not bound: "datadir-zoo-0", which is unexpected.]
or
error finding provisioning plugin for claim test/datadir-zoo-2: cannot find volume plugin for alpha provisioning
Here is my openshift template.yaml
I'm note sure but I suspect that it might be due to line volume.alpha.kubernetes.io/storage-class: anything, because I don't think that there is any default StorageClass defined...
If so how can I set up the most simple StorageClass to get this to work, because as I'm self-hosting my openshift origin cluster, I cannot fit into any of the cloud storage option (GCE, AWS, Azure, etc...)?
I think it actually is more related to the setup of storage on your cluster.
There are several storage options as mentioned at OpenShift Origin: Persistent Storage
If you run it locally, you could use NFS (see OpenShift Origin: Persistent Storage using NFS).
If you run it in minishift or single node cluster, you can use HostPath (see Minishift Persistent Volumes). In this case it would be enough to create a PersistentVolume of size 1GB. Then the PersistentVolumeClaim in your template can be bound.
Related
I am deploying microservices in my openshift cluster but I can see out of 90 microservices nearly 10 got stuck in Init:0/1 status. Is there a way to troubleshoot the issue??
If you are using web page UI.
Go to your developer tab, and go to project.
There you should see the recent events in your project where the errors related to the 0/1 pods stuck state should appear. For me it was something like
Error creating: pods "xxxx" is forbidden: exceeded quota: project-quota, requested: requests.memory=500Mi, used: requests.memory=750Mi, limited: requests.memory=1Gi
So that meant that my project was attempting to have 1.25Gi of memory when 1Gi was the limit
In this case I went down to project quotas in my project screen.
and saw something like this in yaml format:
spec:
hard:
file-share-dr-off.storageclass.storage.k8s.io/requests.storage: xGi
file-share-dr-on.storageclass.storage.k8s.io/requests.storage: xGi
limits.cpu: 'x'
limits.memory: 1Gi
pods: 'x'
requests.cpu: 'x'
requests.memory: 1Gi
vsan.storageclass.storage.k8s.io/requests.storage: xGi
So I increased limits.memory and requests.memory to 2Gi for my project quota and hit save.
After that the pod errors got fixed.
And deployment went from 0/1 to 1/1 pods.
I'm trying to run WordPress by using Kubernetes link, and the only change is I changed 20Gi to 5Gi, but when I run kubectl apply -k ., I get this error:
Error from server (Forbidden): error when creating ".": persistentvolumeclaims "wp-pv-claim" is forbidden: exceeded quota: storagequota, requested: requests.storage=5Gi, used: requests.storage=5Gi, limited: requests.storage=5Gi
I searched but did not find any related answer to mine (or even maybe I'm wrong).
Could you please answer me these questions:
How to solve the above issue?
If the volume's size is limited to 5G, then the pod cannot be bigger than 5G? I mean if I exec into the pod and run a command like dd if=/dev/zero of=file bs=1M count=8000, should it create an 8G file or not? I mean this quota and volume limits whole the pod? Or only a specific path like /var/www/html?
Edit 1
describe pvc mysql-pv-claim
Name: mysql-pv-claim
Namespace: default
StorageClass:
Status: Pending
Volume:
Labels: app=wordpress
Annotations: <none>
Finalizers: [kubernetes.io/pvc-protection]
Capacity:
Access Modes:
VolumeMode: Filesystem
Used By: wordpress-mysql-6c479567b-vzpm5
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal FailedBinding 4m (x222 over 59m) persistentvolume-controller no persistent volumes available for this claim and no storage class is set
I decided to summarize our comments conversation for better readability and visibility.
The issue at first seemed to be caused by resourcequota.
Error from server (Forbidden): error when creating ".": persistentvolumeclaims "wp-pv-claim" is forbidden: exceeded quota: storagequota, requested: requests.storage=5Gi, used: requests.storage=5Gi, limited: requests.storage=5Gi
It looked like there was already existing PVC and it wouldn't allow to create a new one.
OP removed the resource quota although it was not necessary in this case since the real issue was with the PVC.
kubectl describe pvc mysql-pv-claim showed the following event:
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal FailedBinding 4m (x222 over 59m) persistentvolume-controller no persistent volumes available for this claim and no storage class is set
Event message:
persistentvolume-controller no persistent volumes available for this claim and no storage class is set
Since OP created the cluster with kubeadm and kubeadm doesn't come with a predeployed storage provider out of the box; this means that it needs to be added manually. (Storage Provider is a controller that can create a volume and mount it).
Each StorageClass has a provisioner that determines what volume plugin is used for provisioning PVs. This field must be specified. Since there was no storage class in cluster, OP decided to create one and picked Local storage class but forgot that:
Local volumes do not currently support dynamic provisioning [...].
and
Local volumes can only be used as a statically created PersistentVolume. Dynamic provisioning is not supported
This means that a local volume had to be created manually.
Using https://github.com/helm/charts/tree/master/stable/mysql (all the code is here), it is cool being able to run mysql as part of my local kubernetes cluster (using docker kubernetes).
The problem though is that once I stop running the pod, and then run the pod again, all the data that was stored is now gone.
My question is how do I keep the data that was added to the mysql pod? I have read about persistent volumes, and the mysql helm example from github is showing that it is using PersistentVolumeClaim. I have also enabled persistence on the values.yaml file, but I cannot seem to have the same data that was saved in the database.
My docker kubernetes version is currently 1.14.6.
Please verify your msql POD You should notice volumes and volumesMount options:
volumeMounts:
- mountPath: /var/lib/mysql
name: data
.
.
.
volumes:
- name: data
persistentVolumeClaim:
claimName: msq-mysql
In additions please verify your PersistentVolume and PersistentVolumeClaim, storageClass:
kubectl get pv,pvc,pods,sc:
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
persistentvolume/pvc-2c6aa172-effd-11e9-beeb-42010a840083 8Gi RWO Delete Bound default/msq-mysql standard 24m
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
persistentvolumeclaim/msq-mysql Bound pvc-2c6aa172-effd-11e9-beeb-42010a840083 8Gi RWO standard 24m
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
pod/msq-mysql-b5c48c888-pz6p2 1/1 Running 0 4m28s 10.0.0.8 gke-te-1-default-pool-36546f4e-5rgw <none> <none>
Please run kubectl describe persistentvolumeclaim/msq-mysql (in your example you should change the pvc name)
You can notice that pvc was provisioned successfully using gce-pd and mounted by msq-mysql POD.
Normal ProvisioningSucceeded 26m persistentvolume-controller Successfully provisioned volume pvc-2c6aa172-effd-11e9-beeb-42010a840083 using kubernetes.io/gce-pd
Mounted By: msq-mysql-b5c48c888-pz6p2
I have created table with on row, deleted the pod and verified after that (as expected everything is alright):
mysql> SELECT * FROM t;
+------+
| c |
+------+
| ala |
+------+
1 row in set (0.00 sec)
Why: all the data that was stored is now gone.
As per helm chart docs:
The MySQL image stores the MySQL data and configurations at the /var/lib/mysql path of the container.
By default a PersistentVolumeClaim is created and mounted into that directory. In order to disable this functionality you can change the values.yaml to disable persistence and use an emptyDir instead.
Mostly there is problem with pv,pvc binding. It can be also problem with user defined or non default storageClass.
So please verify pv,pvc as stated above.
Take a look at StorageClass
A claim can request a particular class by specifying the name of a StorageClass using the attribute storageClassName. Only PVs of the requested class, ones with the same storageClassName as the PVC, can be bound to the PVC.
PVCs don’t necessarily have to request a class. A PVC with its storageClassName set equal to "" is always interpreted to be requesting a PV with no class, so it can only be bound to PVs with no class (no annotation or one set equal to ""). A PVC with no storageClassName is not quite the same and is treated differently by the cluster, depending on whether the DefaultStorageClass admission plugin is turned on.
My customer asked me if openshift can provide the same control on memory usage as docker can, for example, docker run can have the following parameters to control memory usage when running a container:
--kernel-memory
--memory
--memory-reservation
While I searched the corresponding part in openshift, I found ResoureQuota and LimitRange should work for that, but what if a pod claims itself will use 100Mi memory by using LimitRange but actually it will consume 500Mi memory instead? the memory can still be used "illegally", seems docker with --memory can control this situation more better.
In openshift, is there any method for controlling real memory usage instead of checking what a pod claimed in LimitRange or using "oc set resources dc hello --requests=memory=256Mi"?
Best regards
Lan
As far as my experience with Openshift I have not come across the situation where the POD has consumed more memory or CPU for which it has configured. If in case it reaches the threshold, the POD automatically will be killed and restarts.
You can set the POD resource limits in the Deployment config:
resources:
limits:
cpu: 750m
memory: 1024Mi
The resources can be monitored in the metrics section of the respective POD:
Apart from the indiviual POD settings you can define your own overall project settings for each container in the POD.
$ oc get limits
NAME
limits
$ oc describe limits <NAME>
Name: <NAME>
Namespace: <NAME_SPACE>
Type Resource Min Max Default Request Default Limit Max Limit/Request Ratio
---- -------- --- --- --------------- ------------- -----------------------
Pod memory 256Mi 32Gi - - -
Pod cpu 125m 6400m - - -
Container cpu 125m 6400m 125m 750m -
Container memory 256Mi 32Gi 512Mi 1Gi -
For more information on resource settings refer here.
If you only use --requests=memory=256Mi, you set QoS level to "burstable", which means pod can request at least 256Mi memory without upper limit except reaching project quota. If you want to limit pod memory, use --limit=memory=256Mi instead.
I am trying to run an sonatype/nexus3 on openshift online v3 pro. If I just use the web console to create a new app from image it assigns it only 512Mi and it dies with OOM. It did get created though and logged a lot of java output before it died of out of memory. When using the web console there doesnt appear a way to set the memory on the image. When I try to edited the yaml of the pod it doesn't let me edited the memory limit.
Reading the docs about memory limits it suggests that I can run with this:
oc run nexus333 --image=sonatype/nexus3 --limits=memory=750Mi
Then it doesn't even start. It dies with:
{kubelet ip-172-31-59-148.ec2.internal} Error: Error response from
daemon: {"message":"create
c30deb38b3c26252bf1218cc898fbf1c68d8fc14e840076710c211d58ed87a59:
mkdir
/var/lib/docker/volumes/c30deb38b3c26252bf1218cc898fbf1c68d8fc14e840076710c211d58ed87a59:
permission denied"}
More information from oc get events:
FIRSTSEEN LASTSEEN COUNT NAME KIND SUBOBJECT TYPE REASON SOURCE MESSAGE
16m 16m 1 nexus333-1-deploy Pod Normal Scheduled {default-scheduler } Successfully assigned nexus333-1-deploy to ip-172-31-50-97.ec2.internal
16m 16m 1 nexus333-1-deploy Pod spec.containers{deployment} Normal Pulling {kubelet ip-172-31-50-97.ec2.internal} pulling image "registry.reg-aws.openshift.com:443/openshift3/ose-deployer:v3.6.173.0.21"
16m 16m 1 nexus333-1-deploy Pod spec.containers{deployment} Normal Pulled {kubelet ip-172-31-50-97.ec2.internal} Successfully pulled image "registry.reg-aws.openshift.com:443/openshift3/ose-deployer:v3.6.173.0.21"
15m 15m 1 nexus333-1-deploy Pod spec.containers{deployment} Normal Created {kubelet ip-172-31-50-97.ec2.internal} Created container
15m 15m 1 nexus333-1-deploy Pod spec.containers{deployment} Normal Started {kubelet ip-172-31-50-97.ec2.internal} Started container
15m 15m 1 nexus333-1-rftvd Pod Normal Scheduled {default-scheduler } Successfully assigned nexus333-1-rftvd to ip-172-31-59-148.ec2.internal
15m 14m 7 nexus333-1-rftvd Pod spec.containers{nexus333} Normal Pulling {kubelet ip-172-31-59-148.ec2.internal} pulling image "sonatype/nexus3"
15m 10m 19 nexus333-1-rftvd Pod spec.containers{nexus333} Normal Pulled {kubelet ip-172-31-59-148.ec2.internal} Successfully pulled image "sonatype/nexus3"
15m 15m 1 nexus333-1-rftvd Pod spec.containers{nexus333} Warning Failed {kubelet ip-172-31-59-148.ec2.internal} Error: Error response from daemon: {"message":"create 3aa35201bdf81d09ef4b09bba1fc843b97d0339acfef0c30cecaa1fbb6207321: mkdir /var/lib/docker/volumes/3aa35201bdf81d09ef4b09bba1fc843b97d0339acfef0c30cecaa1fbb6207321: permission denied"}
I am not sure why if I use the web console I cannot assign more memory. I am not sure why running it with oc run dies with the mkdir error. Can anyone tell me how to run sonatype/nexus3 on openshift online pro?
Looking in the documentation I see that it is a Java VM solution.
When using Java 8, memory usage can be DRAMATICALLY IMPROVED using only the following 2 runtime Java VM options:
... "-XX:+UnlockExperimentalVMOptions", "-XX:+UseCGroupMemoryLimitForHeap" ...
I just deployed my container (Spring Boot JAR) that consumed over 650 MB RAM. With just these two (new) options RAM consumption dropped to just 270 MB!!!
So, with these 2 runtime settings all OOM's are left far behind! Enjoy!
You may want to also follow along with the tutorial that is in the OpenShift docs https://docs.openshift.com/online/dev_guide/app_tutorials/maven_tutorial.html
I have had success deploying this in OpenShift Online Pro
Okay the mkdir /var/lib/docker/volumes/ permission denied seems to be that the image needs a /nexus-data mount and that is refused. I saw that by deploying from the web console (dies with OOM) but the edit yaml for the created pod to see the generated volume mount.
Creating the image with the following yaml using cat nexus3_pod.ephemeral.yaml | oc create -f - with the volume mount and explicit memory settings the container will now start up:
apiVersion: "v1"
kind: "Pod"
metadata:
name: "nexus3"
labels:
name: "nexus3"
spec:
containers:
-
name: "nexus3"
resources:
requests:
memory: "1200Mi"
limits:
memory: "1200Mi"
image: "sonatype/nexus3"
ports:
-
containerPort: 8081
name: "nexus3"
volumeMounts:
- mountPath: /nexus-data
name: nexus3-1
volumes:
- emptyDir: {}
name: nexus3-1
Notes
The mage sets -Xmx1200m as documented at sonatype/docker-nexus3. So if you assign memory less than 1200Mi it will crash with OOM when the heap grows over the limit. You may as well set requested and max to be the max heap side anything.
When the allocated memory was too low it crashed die just as it was setting up the DB which corrupted the db log which meant it then got in a crash loop "couldn't load 4 byte from 0 byte file" when I recreated it with more memory. It seems that with an emptyDir the files hang around between crash restarts and memory changes (that's documented behaviour I think). I had to recreate a pod with a different name to get a clean emptyDir and assigned memory of 1200Mi to get it to all start.