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Docker enables more convenient management of single-machine container virtualization, where Docker is located between the operating system layer and the application layer;
Relative traditional virtualization (Kvm,xen):
Docker can be more flexible to implement some of the application layer functions, while the utilization of resources is also higher
Relative application:
Docker can better combine applications with more operating systems (mirroring), reducing the cost of deployment and maintenance
In such a location in a single use Docker for business deployment can feel the quality of ascension; But for cross-machine, large-scale, business-quality assurance, Docker itself is a little less, and traditional operations automation tools, whether deployed on-premises or managed by Docker, are a bit nondescript.
Kubernetes is large-scale, distributed, and ensures the management of highly available Docker clusters.
1: Understanding Kubernets Concept:可以把kuberntes理解为容器级别的自动化运维工具, 之前的针对操作系统(linux, windows)的自动化运维工具比如puppet, saltstack, chef所做的工作是确保代码状态的正确, 配置文件状态的正确, 进程状态的正确, 本质是状态本身的维护; 而kubernetes实际上也是状态的维护, 只不过是容器级别的状态维护; 不过kubernetes在容器级别要做到不仅仅状态的维护, 还需要docker跨机器之间通信的问题.
1:pod
2:replicateion Controller
3:service
整个架构大体分为控制节点和计算节点; 控制节点发命令, 计算节点干活.
First, try to understand the architecture from the diagram itself.
Host Environment
110 and 111 deployment ETCD, 110 as Kubenetes control nodes, 111 and 112 as compute nodes
Environment Preparation :
Yum Install Epel-release
Systemctl Stop Firewalld
Systemctl Disable FIREWALLD
ETCD is a distributed, high-performance, high-availability key-value storage system developed and maintained by CoreOS, inspired by ZooKeeper and Doozer, which is written in the go language and handles log replication through raft consistency algorithms to ensure strong consistency.
Reliable: Use raft to ensure consistency
1: Installation package:
Yum Install Etcd-y
2: Edit configuration:/etc/etcd/etcd.conf
# [Member]
etcd_name=192.168.56.110 #member节点名字 to correspond to the etcd_initial_cluster in the back.
Etcd_data_dir= "/var/lib/etcd/default.etcd" #数据存储目录
#ETCD_SNAPSHOT_COUNTER = "10000"
#ETCD_HEARTBEAT_INTERVAL = "100"
#ETCD_ELECTION_TIMEOUT = "1000"
etcd_listen_peer_urls= "http://192.168.56.110:2380" #集群同步地址与端口
etcd_listen_client_urls= "http://192.168.56.110:4001" #client通信端口
#ETCD_MAX_SNAPSHOTS = "5"
#ETCD_MAX_WALS = "5"
#ETCD_CORS = ""
#
#[cluster]
etcd_initial_advertise_peer_urls= "http://192.168.56.110:2380" #peer初始化广播端口
etcd_initial_cluster= "192.168.56.110=http://192.168.56.110:2380,192.168.56.111=http://192.168.56.111:2380" # Cluster member, Format: $ node name =$ node synchronization port node before using "," separate
Etcd_initial_cluster_state= "New" #初始化状态, will change to existing after initialization
Etcd_initial_cluster_token= "Etcd-cluster" #集群名字
etcd_advertise_client_urls= "http://192.168.56.110:4001" #client广播端口
#ETCD_DISCOVERY = ""
#ETCD_DISCOVERY_SRV = ""
#ETCD_DISCOVERY_FALLBACK = "Proxy"
#ETCD_DISCOVERY_PROXY = ""
#
#[proxy]
#ETCD_PROXY = "Off"
#
#[security]
#ETCD_CA_FILE = ""
#ETCD_CERT_FILE = ""
#ETCD_KEY_FILE = ""
#ETCD_PEER_CA_FILE = ""
#ETCD_PEER_CERT_FILE = ""
#ETCD_PEER_KEY_FILE = ""
Systemctl Enable ETCD
Systemctl Start ETCD
#etcdctl member list
Dial TCP 127.0.0.1:2379:connection refused
#etcd默认连接127.0.0.1 2379 ports, and we 192.168.56.110 4001 Port
# etcdctl-c 192.168.56.110:4001 member List
No endpoints available
#如果依然出现了上面的问题, See if the service starts
# NETSTAT-LNP | grep etcd
TCP 0 0 192.168.56.110:4001 0.0.0.0: LIST EN 18869/ETCD
TCP 0 0 192.168.56.110:2380 0.0.0.0: LISTEN 18869/ETCD #然后查看端口是否畅通
Telnet 192.168.56.111 4001
Trying 192.168.56.111 ...
Connected to 192.168.56.111.
Escape character is ' ^] '.
^c
# etcdctl-c 192.168.56.110:4001 member list
10f1c239a15ba875:name=192.168.56.110 peerurls=http://192. 168.56.110:2380 clienturls=http://192.168.56.110:4001
f7132cc88f7a39fa:name=192.168.56.111 peerURLs=http:// 192.168.56.111:2380 clienturls=http://192.168.56.111:4001
#etcdctl-C 192.168.56.110:4001 mk/coreos.com/network/config ' {"Network": "10.0.0.0/16"} '
{"Network": "10.0.0.0/16"}
# etcdctl-c 192.168.56.110:4001 Get/coreos.com/network/config
{"Network": "10.0.0.0/16"}1: Control node Installation
Yum-y Install Kubernetes
2: Configuration file:/etc/kubernetes/apiserver
###
# kubernetes System Config
#
# The following values is used to configure the Kube-apiserver
#
# The address on the local server to listen.
Kube_api_address= "--address=0.0.0.0"
# The port is on the local server to listen.
Kube_api_port= "--port=8080"
# Port Minions Listen on
Kubelet_port= "--kubelet_port=10250"
# Comma separated list of nodes in the ETCD cluster
#KUBE_ETCD_SERVERS = "--etcd_servers=http://127.0.0.1:4001"
Kube_etcd_servers= "--etcd_servers=http://192.168.56.110:4001,http://192.168.56.111:4001"
# Modify the ETCD service for our configuration
# Address range to use for services
Kube_service_addresses= "--portal_net=192.168.56.150/28"
# outside the network segment, kubenetes to expose the service by changing networks
# Default Admission Control policies
Kube_admission_control= "--admission_control=namespaceautoprovision,limitranger,resourcequota"
# ADD Your own!
Kube_api_args= ""
3: Start the service
There is a problem with the API's startup script
/usr/lib/systemd/system/kube-apiserver.service
[Unit]
Description=kubernetes API Server
Documentation=https://github.com/googlecloudplatform/kubernetes
[Service]
Permissionsstartonly=true
Execstartpre=-/usr/bin/mkdir/var/run/kubernetes
Execstartpre=-/usr/bin/chown-r kube:kube/var/run/kubernetes/
Environmentfile=-/etc/kubernetes/config
Environmentfile=-/etc/kubernetes/apiserver
User=kube
Execstart=/usr/bin/kube-apiserver \
$KUBE _logtostderr \
$KUBE _log_level \
$KUBE _etcd_servers \
$KUBE _api_address \
$KUBE _api_port \
$KUBELET _port \
$KUBE _allow_priv \
$KUBE _service_addresses \
$KUBE _admission_control \
$KUBE _api_args
Restart=on-failure
limitnofile=65536
[Install]
Wantedby=multi-user.target
Systemctl Enable Kube-apiserver Kube-controller-manager Kube-scheduler
Systemctl Restart Kube-apiserver Kube-controller-manager Kube-scheduler
# PS aux | grep kube
Kube 20505 5.4 1.6 45812 30808? SSL 22:05 0:07/usr/bin/kube-apiserver--logtostderr=true--v=0--etcd_servers=http://192.168.56.110:2380 , http://192.168.56.110:2380--address=0.0.0.0--allow_privileged=false--portal_net=192.168.56.0/24--admission_ Control=namespaceautoprovision,limitranger,resourcequota
Kube 20522 1.8 0.6 24036 12064? SSL 22:05 0:02/usr/bin/kube-controller-manager--logtostderr=true--v=0--machines=127.0.0.1--master= http://127.0.0.1:8080
Kube 20539 1.3 0.4 17420 8760? SSL 22:05 0:01/usr/bin/kube-scheduler--logtostderr=true--v=0--master=http://127.0.0.1:8080
# Kubectl Cluster-info
Kubernetes Master is running at http://localhost:8080
2: Compute node Installation
Yum-y Install kubernetes Docker flannel bridge-utils net-tools
###
# kubernetes System Config
#
# The following values is used to configure various aspects of all
# Kubernetes Services, including
#
# Kube-apiserver.service
# Kube-controller-manager.service
# Kube-scheduler.service
# Kubelet.service
# Kube-proxy.service
# Logging to stderr means we get it in the SYSTEMD journal
Kube_logtostderr= "--logtostderr=true"
# Journal message level, 0 is debug
Kube_log_level= "--v=0"
# Should this cluster is allowed to run privileged Docker containers
kube_allow_priv= "--allow_privileged=false"
# How the Controller-manager, scheduler, and proxy find the Apiserver
Kube_master= "--master=http://192.168.56.110:8080" #将改IP改为控制节点IP
# # # #
# kubernetes Kubelet (Minion) Config
# The address for the info server to serve The
kubelet_address= "--address=192.168.56.111" #本机地址
# The port for the INF, set to 0.0.0.0 or ' for all interfaces ' o Server to serve on
kubelet_port= "--port=10250"
# I leave this blank to use the actual hostname
Kubelet_ho Stname= "--hostname_override=192.168.56.111" #本机地址
# Location of the Api-server
kubelet_api_server= "--api_ servers=http://192.168.56.110:8080 "#控制节点地址
# Add your own!
kubelet_args= "--pod-infra-container-image=docker.io/kubernetes/pause:latest"
#kubenet服务的启动需要依赖以pause这个镜像, The default kubenet is downloaded from the Google Image service, and because of * , the download is unsuccessful, and here we specify the image of the Docker
#镜像下载: Docker pull Docker.io/kubernetes/pause
# Flanneld configuration options
# ETCD URL location. Point the server where ETCD runs
Flannel_etcd= "http://192.168.56.110:4001,http://192.168.56.111:4001" #修改为etcd服务地址
# ETCD config key. This is the configuration key, that flannel queries
# for Address range assignment
flannel_etcd_key= "/coreos.com/network"
# any additional options-want to pass
#FLANNEL_OPTIONS = ""
3: Service Modification
Kubernetes Default service startup problem, need to write adjustment
Cat/usr/lib/systemd/system/kubelet.service
[Unit]
Description=kubernetes Kubelet Server
Documentation=https://github.com/googlecloudplatform/kubernetes
After=docker.service
Requires=docker.service
[Service]
Workingdirectory=/var/lib/kubelet
Environmentfile=-/etc/kubernetes/config
Environmentfile=-/etc/kubernetes/kubelet
Execstart=/usr/bin/kubelet \
$KUBE _logtostderr \
$KUBE _log_level \
$KUBELET _api_server \
$KUBELET _address \
$KUBELET _port \
$KUBELET _hostname \
$KUBE _allow_priv \
$KUBELET _args
limitnofile=65535
limitnproc=10240
Restart=on-failure
[Install]
Wantedby=multi-user.target
Systemctl Start Docker
Systemctl Stop Docker
Ifconfig Docker0 Down
Brctl DELBR Docker0
Start the service
Systemctl Enable Kube-proxy Kubelet Flanneld Docker
Systemctl Restart Kube-proxy kubelet Flanneld Docker
# Kubectl Get Nodes
NAME LABELS STATUS
192.168.56.111 kubernetes.io/hostname=192.168.56.111 Ready
192.168.56.112 kubernetes.io/hostname=192.168.56.112 Ready
Kubenetes management is actually for POD, RC, services management, the command line for Kubenetes management recommendations based on the configuration file, so easier to manage, but also more standardized
Kubectl create-h
Create a resource by filename or stdin.
JSON and YAML formats are accepted.
Usage:
Kubectl create-f FILENAME [flags]
Examples:
Create a pod using the data in Pod.json.
$ kubectl create-f Pod.json
Create a pod based on the JSON passed to stdin.
$ Cat Pod.json | Kubectl Create-f-
Format specification:
Kubectl api-versions
Kind:replicationcontroller #Pod, Replicationcontroller, Service
Metadata: #元数据, mostly name and label
Name:test
Spec: #配置, depending on the kind, the specific configuration items will be different
***
+-----------+
| |
| Logic | #逻辑处理服务
| |
+---+--+----+
| |
+----+ +----+
| |
| |
+----V-----+ +----V----+
| | | |
| DB | | Redis | #调用其他服务
| | | |
+----------+ +---------+
idea : Provide a complete set of services within each pod
1: Prepare the mirror
2:RC Configuration Wechat-rc.yaml:
Apiversion:v1beta3
Kind:replicationcontroller
Metadata
Name:wechatv4
Labels
Name:wechatv4
Spec
Replicas:1
Selector
Name:wechatv4
Template
Metadata
Labels
Name:wechatv4
Spec
Containers
-Name:redis
Image:redis
Ports
-containerport:6379
-Name:postgres
image:opslib/wechat_db
Ports
-containerport:5432
-Name:wechat
Image:opslib/wechat1
Ports
-CONTAINERPORT:80
# Kubectl Create-f Wechat-rc.yaml
Replicationcontrollers/wechat
sql_connection= ' Postgresql://wechat:[email protected]/wechat '
Cached_backend= ' redis://127.0.0.1:6379/0 '
Apiversion:v1beta3
Kind:service
Metadata
Name:wechat
Labels
Name:wechat
Spec
Ports
-PORT:80
Selector
Name:wechatv4
# Kubectl Create-f Wechat-service.yaml
Services/wechat
Kubectl Get service WeChat
NAME LABELS SELECTOR IP (s) PORT (s)
WeChat name=wechat name=wechatv4 192.168.56.156 80/tcp
# curl-i http://192.168.56.156
http/1.1 OK
content-length:0
Access-control-allow-headers:x-auth-token, Content-type
server:tornadoserver/4.2
Etag: "da39a3ee5e6b4b0d3255bfef95601890afd80709"
Date:mon, Jul 09:04:49 GMT
Access-control-allow-origin: *
Access-control-allow-methods:get, POST, PUT, DELETE
Content-type:application/json
After the basic business deployment is complete, when the service is to be updated, Kubenetes can take advantage of the rolling update, which basically realizes the hot update of the business.
3.3 Application Management#kubectl rolling-update wechatv3-f Wechatv3.yaml
Creating WECHATV4
At beginning of Loop:wechatv3 replicas:0, WECHATV4 replicas:1
Updating wechatv3 replicas:0, WECHATV4 replicas:1
At end of LOOP:WECHATV3 replicas:0, WECHATV4 replicas:1
Update succeeded. Deleting WECHATV3
Wechatv4
When the same service needs to start multiple instances, the service itself, but the configuration of the startup service is not the same
In general we may have 3 requirements:
You can set different settings for different container in the configuration file.
Apiversion:v1beta3Reference article:
Kind:replicationcontroller
Metadata
Name:new
Labels
Name:new
Spec
Replicas:1
Selector
Name:new
Template
Metadata
Labels
Name:new
Spec
Containers
-Name:redis
Image:redis
Ports
-containerport:6379
-Name:postgres
image:opslib/wechat_db
Ports
-containerport:5432
-Name:wechat
Image:opslib/wechat1
Command: #container的启动命令有外部定义
-'/bin/bash '
-'-C '
-'/usr/bin/wechat_api '
-'--config=/etc/wechat/wechat.conf '
Resources: #限制container的资源
Request: #请求的资源
CPU: "0.5"
Memory: "512Mi"
Limits: #最大可以使用的资源
CPU: "1"
Memory: "1024Mi"
Ports
-CONTAINERPORT:80
Volumemounts: #挂载目录
-Name:data
Mountpath:/data
Volumes
-Name:data
Kubernetes Study Notes
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