kube-dns fails to start - amazon-web-services

I'm trying to install k8s on AWS with kops. The k8s cluster fails to come on line because the kube-dns service keeps crashing. Logs:
I0111 19:21:30.189260 1 logs.go:41] skydns: ready for queries on cluster.local. for tcp://0.0.0.0:10053 [rcache 0]
I0111 19:21:30.189278 1 logs.go:41] skydns: ready for queries on cluster.local. for udp://0.0.0.0:10053 [rcache 0]
I0111 19:21:30.689342 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
...
E0111 19:22:00.189691 1 reflector.go:199] k8s.io/dns/vendor/k8s.io/client-go/tools/cache/reflector.go:94: Failed to list *v1.Endpoints: Get https://100.64.0.1:443/api/v1/endpoints?resourceVersion=0: dial tcp 100.64.0.1:443: i/o timeout
E0111 19:22:00.190016 1 reflector.go:199] k8s.io/dns/vendor/k8s.io/client-go/tools/cache/reflector.go:94: Failed to list *v1.Service: Get https://100.64.0.1:443/api/v1/services?resourceVersion=0: dial tcp 100.64.0.1:443: i/o timeout
All the user kube-system pods are in good order. The api-server log on the master server doesn't list any errors. What might the problem be?

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Slack Bot deployed in Cloud Foundry returns 502 Bad Gateway errors

In Slack, I have set up an app with a slash command. The app works well when I use a local ngrok server.
However, when I deploy the app server to PCF, it is returning 502 errors:
[CELL/0] [OUT] Downloading droplet...
[CELL/SSHD/0] [OUT] Exit status 0
[APP/PROC/WEB/0] [OUT] Exit status 143
[CELL/0] [OUT] Cell e6cf018d-0bdd-41ca-8b70-bdc57f3080f1 destroying container for instance 28d594ba-c681-40dd-4514-99b6
[PROXY/0] [OUT] Exit status 137
[CELL/0] [OUT] Downloaded droplet (81.1M)
[CELL/0] [OUT] Cell e6cf018d-0bdd-41ca-8b70-bdc57f3080f1 successfully destroyed container for instance 28d594ba-c681-40dd-4514-99b6
[APP/PROC/WEB/0] [OUT] ⚡️ Bolt app is running! (development server)
[OUT] [APP ROUTE] - [2021-12-23T20:35:11.460507625Z] "POST /slack/events HTTP/1.1" 502 464 67 "-" "Slackbot 1.0 (+https://api.slack.com/robots)" "10.0.1.28:56002" "10.0.6.79:61006" x_forwarded_for:"3.91.15.163, 10.0.1.28" x_forwarded_proto:"https" vcap_request_id:"7fe6cea6-180a-4405-5e5e-6ba9d7b58a8f" response_time:0.003282 gorouter_time:0.000111 app_id:"f1ea0480-9c6c-42ac-a4b8-a5a4e8efe5f3" app_index:"0" instance_id:"f46918db-0b45-417c-7aac-bbf2" x_cf_routererror:"endpoint_failure (use of closed network connection)" x_b3_traceid:"31bf5c74ec6f92a20f0ecfca00e59007" x_b3_spanid:"31bf5c74ec6f92a20f0ecfca00e59007" x_b3_parentspanid:"-" b3:"31bf5c74ec6f92a20f0ecfca00e59007-31bf5c74ec6f92a20f0ecfca00e59007"
Besides endpoint_failure (use of closed network connection), I also see:
x_cf_routererror:"endpoint_failure (EOF (via idempotent request))"
x_cf_routererror:"endpoint_failure (EOF)"
In PCF, I created an https:// route for the app. This is the URL I put into my Slack App's "Redirect URLs" section as well as my Slash command URL.
In Slack, the URLs end with /slack/events
This configuration all works well locally, so I guess I missed a configuration point in PCF.
Manifest.yml:
applications:
- name: kafbot
buildpacks:
- https://github.com/starkandwayne/librdkafka-buildpack/releases/download/v1.8.2/librdkafka_buildpack-cached-cflinuxfs3-v1.8.2.zip
- https://github.com/cloudfoundry/python-buildpack/releases/download/v1.7.48/python-buildpack-cflinuxfs3-v1.7.48.zip
instances: 1
disk_quota: 2G
# health-check-type: process
memory: 4G
routes:
- route: "kafbot.apps.prod.fake_org.cloud"
env:
KAFKA_BROKER: 10.32.17.182:9092,10.32.17.183:9092,10.32.17.184:9092,10.32.17.185:9092
SLACK_BOT_TOKEN: ((slack_bot_token))
SLACK_SIGNING_SECRET: ((slack_signing_key))
command: python app.py
When x_cf_routererror says endpoint_failure it means that the application has not handled the request sent to it by Gorouter for some reason.
From there, you want to look at response_time. If the response time is high (typically the same value as the timeout, like 60s almost exactly), it means your application is not responding quickly enough. If the value is low, it could mean that there is a connection problem, like Gorouter tries to make a TCP connection and cannot.
Normally this shouldn't happen. The system has a health check in place that makes sure the application is up and listening for requests. If it's not, the application will not start correctly.
In this particular case, the manifest has health-check-type: process which is disabling the standard port-based health check and using a process-based health check. This allows the application to start up even if it's not on the right port. Thus when Gorouter sends a request to the application on the expected port, it cannot connect to the application's port. Side note: typically, you'd only use process-based health checks if your application is not listening for incoming requests.
The platform is going to pass in a $PORT env variable with a value in it (it is always 8080, but could change in the future). You need to make sure your app is listening on that port. Also, you want to listen on 0.0.0.0, not localhost or 127.0.0.1.
This should ensure that Gorouter can deliver requests to your application on the agreed-upon port.

Kafka Multi broker setup with ec2 machine: Timed out waiting for a node assignment. Call: createTopics

I am trying to setup kafka with 3 broker nodes and 1 zookeeper node in AWS EC2 instances. I have following server.properties for every broker:
kafka-1:
broker.id=0
listeners=PLAINTEXT_1://ec2-**-***-**-17.eu-central-1.compute.amazonaws.com:9092
advertised.listeners=PLAINTEXT_1://ec2-**-***-**-17.eu-central-1.compute.amazonaws.com:9092
listener.security.protocol.map=,PLAINTEXT_1:PLAINTEXT
inter.broker.listener.name=PLAINTEXT_1
zookeeper.connect=ec2-**-***-**-105.eu-central-1.compute.amazonaws.com:2181
kafka-2:
broker.id=1
listeners=PLAINTEXT_2://ec2-**-***-**-43.eu-central-1.compute.amazonaws.com:9093
advertised.listeners=PLAINTEXT_2://ec2-**-***-**-43.eu-central-1.compute.amazonaws.com:9093
listener.security.protocol.map=,PLAINTEXT_2:PLAINTEXT
inter.broker.listener.name=PLAINTEXT_2
zookeeper.connect=ec2-**-***-**-105.eu-central-1.compute.amazonaws.com:2181
kafka-3:
broker.id=2
listeners=PLAINTEXT_3://ec2-**-***-**-27.eu-central-1.compute.amazonaws.com:9094
advertised.listeners=PLAINTEXT_3://ec2-**-***-**-27.eu-central-1.compute.amazonaws.com:9094
listener.security.protocol.map=,PLAINTEXT_3:PLAINTEXT
inter.broker.listener.name=PLAINTEXT_3
zookeeper.connect=ec2-**-***-**-105.eu-central-1.compute.amazonaws.com:2181
zookeeper:
tickTime=2000
dataDir=/var/lib/zookeeper
clientPort=2181
When I ran following command in zookeeper I see that they are connected
I also telnetted from any broker to other ones with broker port they are all connected
However, when I try to create topic with 2 replication factor I get Timed out waiting for a node assignment
I cannot understand what is incorrect with my setup, I see 3 nodes running in zookeeper, but having problems when creating topic. BTW, when I make replication factor 1 I get the same error. How can I make sure that everything is alright with my cluster?
It's good that telnet checks the port is open, but it doesn't verify the Kafka protocol works. You could use kcat utility for that, but the fix includes
listeners are set to either PLAINTEXT://:9092 or PLAINTEXT://0.0.0.0:9092 for every broker, which means using the same port
Removing the number from the listener mapping and advertised listeners property such that each broker is the same
I'd also recommend looking at using Ansible/Terraform/Cloudformation to ensure you consistently modify the cluster rather than edit individual settings manually

Google Cloud Run not scaling up despite large backlog and available instances

I am seeing something similar to this post. It looked like additional detail was needed to answer that question, so I'm re-asking with my details since those details weren't provided.
I am running a modified version of the Google Cloud Run image processing tutorial example.
I am inserting tasks into a task queue using this create tasks snippet. The tasks from the queue get pushed to my cloud run instance.
The problem is it isn't scaling up and making it through my tasks in a timely manner.
My cloud run service configuration:
I have tried setting a minimum of both 0 and 50 instances
I have tried a maximum of 100 and 1000 instances
I have tried --concurrency=1 and 2, and 8
I have tried with --async and without --async
With 50 instances pre-allocated even with concurrency set to 1, I am typically seeing ~10 active container instances and ~40 idle container instances. I have ~30,000 tasks in the queue and it is getting through ~5 jobs/minute.
My tasks queue has the default settings. My containers aren't using a lot of cpu, but they are using a lot of memory.
A process takes about a minute to complete. I'm only running one process per container instance. What additional parameters should be set to get higher throughput?
Edit - adding additional logs
I enabled the logs for the queue, I'm seeing some errors for some of the jobs. The errors look like this:
{
insertId: "<my_id>"
jsonPayload: {
#type: "type.googleapis.com/google.cloud.tasks.logging.v1.TaskActivityLog"
attemptResponseLog: {
attemptDuration: "19.453155s"
dispatchCount: "1"
maxAttempts: 0
responseCount: "0"
retryTime: "2021-10-20T22:45:51.559121Z"
scheduleTime: "2021-10-20T16:42:20.848145Z"
status: "UNAVAILABLE"
targetAddress: "POST <my_url>"
targetType: "HTTP"
}
task: "<my_task>"
}
logName: "<my_log_name>"
receiveTimestamp: "2021-10-20T22:45:52.418715942Z"
resource: {
labels: {
location: "us-central1"
project_id: "<my_project>"
queue_id: "<my-queue>"
target_type: "HTTP"
}
type: "cloud_tasks_queue"
}
severity: "ERROR"
timestamp: "2021-10-20T22:45:51.459232147Z"
}
I don't see errors in the cloud run logs.
Edit - Additional Debug Information
I tried to take the queue out of the equation to determine if it is cloud run or the queue. Instead I directly used curl to post to the url. Some of the tasks ran successfully, for others I received an error. In the below logs empty lines are successful:
upstream connect error or disconnect/reset before headers. reset reason: connection termination
upstream connect error or disconnect/reset before headers. reset reason: connection termination
upstream connect error or disconnect/reset before headers. reset reason: connection termination
upstream connect error or disconnect/reset before headers. reset reason: connection termination
upstream connect error or disconnect/reset before headers. reset reason: connection termination
This makes me think cloud run isn't handling all of the incoming requests.
Edit - task completion time test
I wanted to test if the time it takes to complete a task causes any issues with CloudRun and the Queue scaling up and keeping up with the tasks.
In place of the task I actually want completed I put a dummy task that just sleeps for n seconds and prints the task details to stdout (which I can read in the cloud run logs).
With n set to 0, 5, 10 seconds I see the number of instances scale up and it keeps up with the tasks being added to the queue. With n set to 20 seconds or more I see that less CloudRun instances are instantiated and items accumulate in the task queue. I see more errors with the Unavailable status in my logs.
According to this post:
Cloud Run offers a longer request timeout duration of up to 60 minutes
So it seems that long running tasks are expected. Is this a Google bug or am I missing setting some parameter?
I do not think this is a Cloud Run Service problem. I think this is an issue with how you have Tasks setup.
The dates in the log entry look odd. Take a look at the receiveTimestamp and the scheduleTime. The task is scheduled for six hours before the receive time. Do you have a timezone problem?
According to the documentation, if the response_time is not set then the task was not attempted. It looks like you are scheduling tasks incorrectly and the tasks never run.
Search for the text The status of a task attempt. in this link:
Types for Google Cloud Tasks

wso2am-analytics 2.2.0 spark on offset 0

Installing wso2am-analytics-2.2.0 on the port offset 0, then I get error messages as
WARN {org.apache.spark.scheduler.TaskSetManager} - Lost task 0.0 in stage 2990.0 (TID 147439, 10.0.11.26): FetchFailed(BlockManagerId(0, someserver.compute.internal, 12001), shuffleId=745, mapId=0, reduceId=0, message=
org.apache.spark.shuffle.FetchFailedException: Failed to connect to ip-10-0-17-131.eu-central-1.compute.internal:12001
Apparently somewhere is configured to connect to port 12001 (while seems the server listens on 12000)
Where could I configure the port 12000?
Thanks
This port is defined in <Product_Home>repository/conf/analytics/spark/spark-defaults.conf. Property name is spark.blockManager.port. However you shouldn't manually configure it.
This particular issue is a connectivity problem in my knowledge. DAS uses 1200x range ports to spark executor communications. So incase of multiple executors or new executor spawning in and event of one executor getting killed incremented port will be opened. Hence at the network level also we should allow traffic through that port range. So opening that port range in your network interface ip-10-0-17-131.eu-central-1.compute.internal will solve your issue.

Spark - Remote Akka Client Disassociated

I am setting up Spark 0.9 on AWS and am finding that when launching the interactive Pyspark shell, my executors / remote workers are first being registered:
14/07/08 22:48:05 INFO cluster.SparkDeploySchedulerBackend: Registered executor:
Actor[akka.tcp://sparkExecutor#ip-xx-xx-xxx-xxx.ec2.internal:54110/user/
Executor#-862786598] with ID 0
and then disassociated almost immediately, before I have the chance to run anything:
14/07/08 22:48:05 INFO cluster.SparkDeploySchedulerBackend: Executor 0 disconnected,
so removing it
14/07/08 22:48:05 ERROR scheduler.TaskSchedulerImpl: Lost an executor 0 (already
removed): remote Akka client disassociated
Any idea what might be wrong? I've tried adjusting the JVM options spark.akka.frameSize and spark.akka.timeout, but I'm pretty sure this is not the issue since (1) I'm not running anything to begin with, and (2) my executors are disconnecting a few seconds after startup, which is well within the default 100s timeout.
Thanks!
Jack
I had a very similar problem, if not the same.
It started to work for me once the workers were connecting to master by using the very same name as the master thought it had.
My log messages were something like:
ERROR remote.EndpointWriter: AssociationError [akka.tcp://sparkWorker#idc1-hrm1.heylinux.com:7078] -> [akka.tcp://sparkMaster#vagrant-centos64.vagrantup.com:7077]: Error [Association failed with [akka.tcp://sparkMaster#vagrant-centos64.vagrantup.com:7077]].
ERROR remote.EndpointWriter: AssociationError [akka.tcp://sparkWorker#192.168.121.127:7078] -> [akka.tcp://sparkMaster#idc1-hrm1.heylinux.com:7077]: Error [Association failed with [akka.tcp://sparkMaster#idc1-hrm1.heylinux.com:7077]]
WARN util.Utils: Your hostname, idc1-hrm1 resolves to a loopback address: 127.0.0.1; using 192.168.121.187 instead (on interface eth0)
So check the log of the master and see what name it thinks it has.
Then use that very same name on the workers.