Tuesday, January 15, 2019

Kubernetes Cheat Sheet

Kubernetes Cheat Sheet

Run curl test temporarily 
kubectl run --rm mytest --image=yauritux/busybox-curl -it
Run wget test temporarily 
kubectl run --rm mytest --image=busybox -it
Run nginx deployment with 2 replicas 
kubectl run my-nginx --image=nginx --replicas=2 --port=80
List everything 
kubectl get all --all-namespaces
List pods with nodes info 
kubectl get pod -o wide
Show nodes with labels
kubectl get nodes --show-labels
Validate yaml file with dry run
kubectl create --dry-run --validate -f pod-dummy.yaml
Start a temporary pod for testing
kubectl run --rm -i -t --image=alpine test-$RANDOM -- sh
kubectl run shell command
kubectl exec -it mytest -- ls -l /etc/hosts
Get system conf via configmap
kubectl -n kube-system get cm kubeadm-config -o yaml
Explain resource kubectl explain pods
kubectl explain svc
Get all services
kubectl get service --all-namespaces
Watch pods
kubectl get pods -n wordpress --watch
Query healthcheck endpoint
curl -L
Open a bash terminal in a pod
kubectl exec -it storage sh
Check pod environment variables
kubectl exec redis-master-ft9ex env
Enable kubectl shell autocompletion
echo "source <(kubectl completion bash)" >>~/.bashrc, and reload
Get services sorted by name
kubectl get services –sort-by=.metadata.name
Get pods sorted by restart count
kubectl get pods –sort-by=’.status.containerStatuses[0].restartCount’
Get node resource usage
kubectl top node
Get pod resource usage
kubectl top pod
Get resource usage for a given pod
kubectl top <podname> --containers
List resource utilization for all containers
kubectl top pod --all-namespaces --containers=true
Delete pod
kubectl delete pod/<pod-name> -n <my-namespace>
Delete pod by force
kubectl delete pod/<pod-name> --grace-period=0 --force
Delete pods by labels
kubectl delete pod -l env=test
Delete deployments by labels
kubectl delete deployment -l app=wordpress
Delete all resources filtered by labels
kubectl delete pods,services -l name=myLabel
Delete resources under a namespace
kubectl -n my-ns delete po,svc --all
Delete persist volumes by labels
kubectl delete pvc -l app=wordpress
Delete statefulset only (not pods)
kubectl delete sts/<stateful_set_name> --cascade=false
List all pods
kubectl get pods
List pods for all namespace
kubectl get pods -all-namespaces
List all critical pods
kubectl get -n kube-system pods -a
List pods with more info
kubectl get pod -o wide, kubectl get pod/<pod-name> -o yaml
Get pod info
kubectl describe pod/srv-mysql-server
List all pods with labels
kubectl get pods --show-labels
List running pods
kubectl get pods –field-selector=status.phase=Running
Get Pod initContainer status
kubectl get pod --template '{{.status.initContainerStatuses}}' <pod-name>
kubectl run command
kubectl exec -it -n “$ns” “$podname” – sh -c “echo $msg >>/dev/err.log”

Friday, December 28, 2018

Docker Cheat sheet

Docker Cheat sheet

Pull an image from a registry
docker pull alpine:3.4

Retag a local image with a new image name and tag
docker tag alpine:3.4 myrepo/myalpine:3.4

Log in to a registry (the Docker Hub by default)
docker login my.registry.com:8000
Push an image to a registry
docker push myrepo/myalpine:3.4
List all images that are locally stored with the Docker engine
docker images
Delete an image from the local image store
docker rmi alpine:3.4
Create a Docker from image
docker run
--rm #remove container automatically after it exits
-it #connect the container to terminal
--name web #name the container
-p 5000:80 #expose port 5000 externally and map to port 80
-v ~/dev:/code #create a host mapped volume inside the container
alpine:3.4 #the image from which the container is instantiated
/bin/sh #the command to run inside the container
Stop a running container through SIGTERM
docker stop web
Stop a running container through SIGKILL
docker kill web
Create an overlay network and specify a subnet
docker network create --subnet --gateway -d overlay mynet
List the networks
docker network ls
List the running containers
docker ps
List the all running/stopped containers
docker ps -a

Stop a container
docker stop <container­name>

Stop a container (timeout = 1 second)
docker stop t 1 <container­name>
Delete all running and stopped containers
docker rm -f $(docker ps -aq)

Remove all stopped containers
docker rm $(docker ps q f "status=exited”)
Create a new bash process inside the container and connect it to the terminal
docker exec -it web bash
Print the last 100 lines of a container’s lo
docker logs --tail 100 web

Exporting image to an external file
docker save o <filename>.tar [username/]<image­name>[:tag]

Importing and image to an external file
docker load i <filename>.tar 

Inspecting docker image
docker inspect <Container-ID>

Attach to a running container 
docker attach <Container-ID>

Detach from the Container with out killing it ##turn interactive mode to daemon mode
Type Ctrl + p , Ctrl + q

Set the container to be read-only:
docker run --read-only

Flatten an image
ID=$(docker run -d image-name /bin/bash)
docker export $ID | docker import – flat-image-name

To check the CPU, memory, and network I/O usage
docker stats <container>
Build an image from the Dockerfile in the current directory and tag the image
docker build -t myapp:1.0 .

Docker file samples

vi Dockerfile
FROM ubuntu
RUN apt-get update
RUN apt-get install -y nginx
COPY index.html /usr/share/nginx/html/
ENTRYPOINT [“/usr/sbin/nginx”,”-g”,”daemon off;”]
Build new images, create all containers, and start all containers (Compose). (This will not rebuild images if a Dockerfile changes.)
docker-compose up

Build, create, and start all in the background (Compose):
docker-compose up -d

Rebuild all images, create all containers, and start all containers (Compose):
docker-compose up --build

Create a new container for my_service in docker-compose.yml and run the echo command instead of the specified command:
docker-compose run my_service echo "hello"

Run a container with a volume named my_volume mounted at /my/path in the Docker container. (The volume will be created if it doesn't already exist.) 
docker run --mount source=my_volume,target=/my/path my-image
docker run -v my_volume:/my/path my-image

Copy my-file.txt from the host current directory to the /tmp directory in my_container:
docker cp ./my-file.txt my_container:/tmp/my-file.txt

Inspect an container
docker inspect python_web | less 

Sunday, July 22, 2018

Deploying Kafka into ubuntu

Apache Kafka is a distributed message broker designed to handle large volumes of real-time data efficiently. Unlike traditional brokers like ActiveMQ and RabbitMQ, Kafka runs as a cluster of one or more servers which makes it highly scalable and due to this distributed nature it has inbuilt fault-tolerance while delivering higher throughput when compared to its counterparts

 Implementation Steps Single Node

3.1. Installing a Single Node Kafka

3.1.1. Installing Java

sudo apt-get update
sudo apt-get install default-jre

3.1.2. Installing zookeeper

sudo apt-get install zookeeperd

3.1.3. Create a service User for Kafka

sudo adduser --system --no-create-home --disabled-password --disabled-login kafka

3.1.4. Installing Kafka

3.1.5. Download Kafka

cd ~

curl http://kafka.apache.org/KEYS | gpg --import
wget https://dist.apache.org/repos/dist/release/kafka/1.0.1/kafka_2.12-1.0.1.tgz.asc
gpg --verify kafka_2.12-1.0.1.tgz.asc kafka_2.12-1.0.1.tgz

3.1.6. Create a directory for extracting Kafka

sudo mkdir /opt/kafka
sudo tar -xvzf kafka_2.12-1.0.1.tgz --directory /opt/kafka --strip-components 1

3.1.7. Delete Kafka tarball and .asc file

rm -rf kafka_2.12-1.0.1.tgz kafka_2.12-1.0.1.tgz.asc

3.1.8. Configuring Kafka Server

Setup Kafka to start automatically on bootup

Copy the following init script to /etc/init.d/kafka:
# Check that networking is up.
#[ ${NETWORKING} = "no" ] && exit 0


# See how we were called.
case "$1" in
       # Start daemon.
       echo "Starting $DAEMON_NAME";
       nohup $DAEMON_PATH/kafka-server-start.sh -daemon /opt/kafka/config/server.properties
       # Stop daemons.
       echo "Shutting down $DAEMON_NAME";
       pid=`ps ax | grep -i 'kafka.Kafka' | grep -v grep | awk '{print $1}'`
       if [ -n "$pid" ]
         kill -9 $pid
         echo "Kafka was not Running"
       $0 stop
       sleep 2
       $0 start
       pid=`ps ax | grep -i 'kafka.Kafka' | grep -v grep | awk '{print $1}'`
       if [ -n "$pid" ]
         echo "Kafka is Running as PID: $pid"
         echo "Kafka is not Running"
       echo "Usage: $0 {start|stop|restart|status}"
       exit 1

exit 0
======*** Make the kafka service

sudo chmod 755 /etc/init.d/kafka
sudo update-rc.d kafka defaults Start Stop the Kafka Services

sudo service kafka start
sudo service kafka status
sudo service kafka stop

3.1.9. Testing kafka topics Starting Kafka

sudo service kafka start
sudo service kafka status Topic creation

/opt/kafka/bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1 --topic test Publish Msg to test topic

/opt/kafka/bin/kafka-console-producer.sh --broker-list localhost:9092 --topic test

This will prompt for Msgs,  we can enter a test Msg Consume Msg from topic

/opt/kafka/bin/kafka-console-consumer.sh --zookeeper localhost:2181 --topic test --from-beginning

3.2. Making Kafka Scalable

Clustering the Zookeeper in all the Servers
Clustering the kafka in All the servers

Install Zookeeper in all the server and configure the servers in

to mention all the nodes of zookeeper


Once kafka is installed in all the servers

We will change the following settings.

broker.id should be unique for each node in the cluster.

for node-2 broker.id=1
for node-3 broker.id=2
change zookeeper.connect value to have such that it lists all zookeeper hosts with port


Sunday, April 15, 2018

Enabling hive Authorization in Qubole

Once the Hive authorization is enabled in qubole we need to mange the users and permission by hive authentication,  following are the some of the commands which will be used for the same.

1. Listing the Current Roles

Set role admin;
show roles

2. Create the roles

CREATE ROLE <role_name>;
Creates a new role. Only the admin role has privilege for this.

Set role admin;
Create role sysadmin;

3. Grant Role to users

GRANT ROLE <role_name> TO USER <user_name>
Set role admin;
Grant Role sysadmin to user rahul ;

4. Revoke a role from user

REVOKE ROLE <role_name> FROM USER <user_name>;

Set role admin;
REVOKE Role sysadmin from user rahul;

5. List  Roles attached to a user


Set role admin;
show role grant user `rahul`;

6. List Users under a role


Set role admin;

7. Assign Role access to tables

Sample Permission
SELECT privilege: It provides read access to an object (table).
INSERT privilege: It provides ability for adding data to an object (table).
UPDATE privilege: It provides ability for running UPDATE queries on an object (table).
DELETE privilege: It provides ability for deleting data in an object (table).
ALL privilege: It provides all privileges. In other words, this privilege gets translated into all the above privileges.

GRANT <Permission> ON <table_name> TO ROLE <role_name>;

Grant all on default.testtable to role sysadmin

8. View Role/user Permissions on tables

Check all users who have been granted with a specific role

SHOW GRANT USER <user_name> ON <table_name|All>;
SHOW GRANT ROLE <user_name> ON <table_name|All>;

SHOW GRANT user analytics on all