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How to integrate docker in Kubernetes? in view of this problem, this article introduces the corresponding analysis and solution in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible way.

K8s is a container cluster management system, which provides functions such as resource scheduling, balanced disaster recovery, service registration, dynamic capacity expansion and so on.

Introduction to Kubernetes components:

Etcd: stores Kubernetes information, various business container information, etc., and stores flannel network configuration information for coordination among nodes. It's kubernetes's database.

Flannel: for cross-host network communication between multiple containers

Management Interface of kube-apiserver:k8s

Kube-controller-manager: performing Kubernetes services

Kube-scheduler: container startup, migration, expansion and reduction scheduling

Kubelet: the actual operator of the container

Kube-proxy: reverse proxy for container network

Prepare:

1. Turn off centos7's firewall firewalld

$systemctl stop firewalld

$systemctl disable firewalld

two。 Install NTP and make sure it is enabled and running

$yum-y install ntp

$systemctl start ntpd

$systemctl enable ntpd

Configure Kubernetes Master:

Perform the following steps on master

1. Install etcd and Kubernetes through yum:

$yum-y install etcd kubernetes

two。 Configure all addresses in etcd snooping / etc/etcd/etcd.conf:

ETCD_NAME=default

ETCD_DATA_DIR= "/ var/lib/etcd/default.etcd"

ETCD_LISTEN_CLIENT_URLS= "http://0.0.0.0:2379"

ETCD_ADVERTISE_CLIENT_URLS= "http://localhost:2379"

3. Configure the Kubernetes interface service, / etc/kubernetes/apiserver

KUBE_API_ADDRESS= "--address=0.0.0.0"

KUBE_API_PORT= "--port=8080"

KUBELET_PORT= "--kubelet_port=10250"

KUBE_ETCD_SERVERS= "--etcd_servers= http://127.0.0.1:2379"

KUBE_SERVICE_ADDRESSES= "--service-cluster-ip-range=10.254.0.0/16"

KUBE_ADMISSION_CONTROL= "--admission_control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ResourceQuota"

KUBE_API_ARGS= ""

4. Start and enable etcd, kube-apiserver, kube- controllermanager, and kube-scheduler:

$for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler; do

Systemctl restart $SERVICES

Systemctl enable $SERVICES

Systemctl status $SERVICES

Done

5. Define flannel configuration in etcd

$etcdctl mk / atomic.io/network/config'{"Network": "172.17.0.0max 16"}'

6. Check the status of the node. There is no information because it has not been started yet.

$kubectl get nodes

NAME LABELS STATUS

Configure the Kubernetes Minions node:

The following steps are performed on minion1, minion2, and minion3

1. Install flannel and Kubernetes

$yum-y install flannel kubernetes

two。 Configure the etcd server for the flannel service. The following line in update / etc/sysconfig/flanneld connects to the master server:

FLANNEL_ETCD= "http://192.168.204.30:2379"

3. Configure the main service interface of Kubernetes in / etc/kubernetes/config

KUBE_MASTER= "--master= http://192.168.204.30:8080"

4. Configuration / etc/kubernetes/kubelet

Minion1:

KUBELET_ADDRESS= "--address=0.0.0.0"

KUBELET_PORT= "--port=10250"

# change the hostname to this host's IP address

KUBELET_HOSTNAME= "--hostname_override=192.168.204.31"

KUBELET_API_SERVER= "--api_servers= http://192.168.204.30:8080"

KUBELET_ARGS= ""

Minion2:

KUBELET_ADDRESS= "--address=0.0.0.0"

KUBELET_PORT= "--port=10250"

# change the hostname to this host's IP address

KUBELET_HOSTNAME= "--hostname_override=192.168.204.32"

KUBELET_API_SERVER= "--api_servers= http://192.168.204.30:8080"

KUBELET_ARGS= ""

Minion3:

KUBELET_ADDRESS= "--address=0.0.0.0"

KUBELET_PORT= "--port=10250"

# change the hostname to this host's IP address

KUBELET_HOSTNAME= "--hostname_override=192.168.204.33"

KUBELET_API_SERVER= "--api_servers= http://192.168.204.30:8080"

KUBELET_ARGS= ""

5. Start the kube-proxy, kubelet, docker, and flanneld services:

$for SERVICES in kube-proxy kubelet docker flanneld; do

Systemctl restart $SERVICES

Systemctl enable $SERVICES

Systemctl status $SERVICES

Done

6. Check for docker0 and flannel0 on each minion. Different ranges of IP addresses can be obtained on flannel0

Minion1:

$ip a | grep flannel | grep inet

Inet 172.17.59.0/16 scope global flannel0

Minion2:

$ip a | grep flannel | grep inet

Inet 172.17.19.0/16 scope global flannel0

Minion3:

$ip a | grep flannel | grep inet

Inet 172.17.80.0/16 scope global flannel0

7. Check node status

$kubectl get nodes

NAME STATUS AGE

192.168.204.31 Ready 8m

192.168.204.32 Ready 7m

192.168.204.33 Ready 7m

The Kubernetes cluster is already configured and running. Start configuring pods

Configure pods (Containers)

1. Define a yaml file in Kubernetes master and use the kubectl command to create a pods based on the definition. Create a mysql.yaml file:

$mkdir pods

$cd pods

$vim mysql.yaml

two。 Add the following lines:

ApiVersion: v1

Kind: Pod

Metadata:

Name: mysql

Labels:

Name: mysql

Spec:

Containers:

-resources:

Limits:

Cpu: 1

Image: mysql

Name: mysql

Env:

-name: MYSQL_ROOT_PASSWORD

# change this

Value: yourpassword

Ports:

-containerPort: 3306

Name: mysql

3. Create pod

$kubectl create-f mysql.yaml

4. Verify the creation and operation of pod:

$kubectl get pods

POD IP CONTAINER (S) IMAGE (S) HOST LABELS STATUS CREATED

Mysql 172.17.38.2 mysql mysql 192.168.204.32/192.168.204.32 name=mysql Running 3 hours

Kubernetes created a Docker container in 192.168.204.32. Now you need to create a service that allows other pods to access the mysql database on known ports and hosts.

Create a service

1. There is a MySQL pod in 192.168.204.32, which defines a mysql-service.yaml

ApiVersion: v1

Kind: Service

Metadata:

Labels:

Name: mysql

Name: mysql

Spec:

ExternalIPs:

-192.168.204.32

Ports:

# this port is the port of the service

-port: 3306

# label keys and values that must match in order to receive traffic for this service

Selector:

Name: mysql

two。 Run the service

$kubectl create-f mysql-service.yaml

Report exception: Error from server (BadRequest): error when creating "mysql.yaml": Pod in version "v1" cannot be handled as a Pod: [pos 177]: json: expect char'"'but got char' 1'

3. To view the service, 10.254.x.x is the internal IP address of the Kubernetes defined in / etc/kubernetes/apiserver, so the network ip connected to the outside is defined:

$kubectl get services

NAME LABELS SELECTOR IP PORT (S)

Kubernetes component=apiserver,provider=kubernetes 10.254.0.2 443/TCP

Kubernetes-ro component=apiserver,provider=kubernetes 10.254.0.1 80/TCP

Mysql name=mysql name=mysql 10.254.13.156 3306/TCP

192.168.204.32

4. External connection to the database

$mysql-uroot-p-h292.168.204.32

MySQL [(none)] > show variables like'% version%'

+-- +

| | Variable_name | Value |

+-- +

| | innodb_version | 5.6.24 |

| | protocol_version | 10 | |

| | slave_type_conversions |

| | version | 5.6.24 |

| | version_comment | MySQL Community Server (GPL) |

| | version_compile_machine | x86room64 | |

| | version_compile_os | Linux |

+-- +

7 rows in set (0.01 sec)

This is the answer to the question about how to integrate docker in Kubernetes. I hope the above content can be of some help to you. If you still have a lot of doubts to solve, you can follow the industry information channel for more related knowledge.

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