k8s環境下GitLab+Helm+GitLab Runner Java專案CICD落地實踐
背景
目前使用5臺伺服器搭建了Kubernetes
叢集環境,監控、日誌採集均已落地,業務也手工遷移到叢集中順利執行,故需要將原本基於原生docker
環境的CICD流程遷移到Kubernetes
叢集中
優勢
Kubernetes
叢集實現CICD有幾個顯著優勢
-
Deployment
天然支援滾動部署、結合其他Kubernetes
特性還能實現藍綠部署、金絲雀部署等 - 新版本的
GitLab
與GitLab Runner
天然支援Kubernetes
叢集,支援runner
自動伸縮,減小資源佔用
環境
Kubernetes
版本:1.14
GitLab
版本:12.2.5
GitLab-Runner
版本:12.1.0
Docker
環境版本:17.03.1
GitLab-Runner部署
配置介紹
原始環境的gitlab runner
通過手動執行官網提供的註冊命令和啟動命令,分成兩部部署,需要較多的手工操作,而在Kubernetes
中,其支援使用Helm
一鍵部署,官方檔案如下
其實官方檔案的指引並不清晰,許多配置在檔案中沒有介紹用法,推薦去其原始碼倉庫檢視詳細的引數使用檔案
其中介紹了幾個關鍵配置,在後面修改工程的ci
配置檔案時會用到
使用DinD方式構建已經不再推薦
官方檔案介紹
Use docker-in-docker workflow with Docker executor
The second approach is to use the special docker-in-docker (dind) Docker image with all tools installed (
docker
) and run the job script in context of that image in privileged mode.Note:
docker-compose
is not part of docker-in-docker (dind). To usedocker-compose
in your CI builds,follow thedocker-compose
installation instructions.Danger: By enabling
--docker-privileged
,you are effectively disabling all of the security mechanisms of containers and exposing your host to privilege escalation which can lead to container breakout. For more information,check out the official Docker documentation on Runtime privilege and Linux capabilities.Docker-in-Docker works well,and is the recommended configuration,but it is not without its own challenges:
- When using docker-in-docker,each job is in a clean environment without the past history. Concurrent jobs work fine because every build gets it’s own instance of Docker engine so they won’t conflict with each other. But this also means jobs can be slower because there’s no caching of layers.
- By default,Docker 17.09 and higher uses
--storage-driver overlay2
which is the recommended storage driver. See Using the overlayfs driver for details.- Since the
docker:19.03.1-dind
container and the Runner container don’t share their root filesystem,the job’s working directory can be used as a mount point for child containers. For example,if you have files you want to share with a child container,you may create a subdirectory under/builds/$CI_PROJECT_PATH
and use it as your mount point (for a more thorough explanation,check issue #41227):
總之使用DinD
進行容器構建並非不可行,但面臨許多問題,例如使用overlay2
網路需要Docker版本高於 17.09
Using
docker:dind
Running the
docker:dind
also known as thedocker-in-docker
image is also possible but sadly needs the containers to be run in privileged mode. If you're willing to take that risk other problems will arise that might not seem as straight forward at first glance. Because the docker daemon is started as aservice
usually in your.gitlab-ci.yaml
it will be run as a separate container in your Pod. Basically containers in Pods only share volumes assigned to them and an IP address by which they can reach each other usinglocalhost
./var/run/docker.sock
is not shared by thedocker:dind
container and thedocker
binary tries to use it by default.To overwrite this and make the client use TCP to contact the Docker daemon,in the other container,be sure to include the environment variables of the build container:
DOCKER_HOST=tcp://localhost:2375
for no TLS connection.DOCKER_HOST=tcp://localhost:2376
for TLS connection.Make sure to configure those properly. As of Docker 19.03,TLS is enabled by default but it requires mapping certificates to your client. You can enable non-TLS connection for DIND or mount certificates as described in Use Docker In Docker Workflow wiht Docker executor
在Docker 19.03.1版本之後預設開啟了TLS
配置,在構建的環境變數中需要宣告,否則報連線不上docker
的錯誤,並且使用DinD
構建需要runner
開啟特權模式,以訪問主機的資源,並且由於使用了特權模式,在Pod
中對runner
需要使用的資源限制將失效
使用Kaniko構建Docker映象
目前官方提供另一種方式在docker
容器中構建並推送映象,實現更加優雅,可以實現無縫遷移,那就是kaniko
Building a Docker image with kaniko
其優勢官網描述如下
在Kubernetes叢集中構建Docker映像的另一種方法是使用kaniko。iko子
- 允許您構建沒有特權訪問許可權的映像。
- 無需Docker守護程式即可工作。
在後面的實踐中會使用兩種方式構建Docker映象,可根據實際情況選擇
使用Helm部署
拉取Helm
Gitlab-Runner
倉庫到本地,修改配置
將原有的gitlab-runner
配置遷移到Helm
中,遷移後如下
image: alpine-v12.1.0
imagePullPolicy: IfNotPresent
gitlabUrl: https://gitlab.fjy8018.top/
runnerRegistrationToken: "ZXhpuj4Dxmx2tpxW9Kdr"
unregisterRunners: true
terminationGracePeriodSeconds: 3600
concurrent: 10
checkInterval: 30
rbac:
create: true
clusterWideAccess: false
metrics:
enabled: true
listenPort: 9090
runners:
image: ubuntu:16.04
imagePullSecrets:
- name: registry-secret
locked: false
tags: "k8s"
runUntagged: true
privileged: true
pollTimeout: 180
outputLimit: 4096
cache: {}
builds: {}
services: {}
helpers: {}
resources:
limits:
memory: 2048Mi
cpu: 1500m
requests:
memory: 128Mi
cpu: 200m
affinity: {}
nodeSelector: {}
tolerations: []
hostAliases:
- ip: "192.168.1.13"
hostnames:
- "gitlab.fjy8018.top"
- ip: "192.168.1.30"
hostnames:
- "harbor.fjy8018.top"
podAnnotations: {}
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其中配置了私鑰、內網harbor
地址、harbor
拉取資源私鑰,資源限制策略
GitLab-Runner選擇可能導致的坑
選擇runner
映象為alpine-v12.1.0
,這一點單獨說一下,目前最新的runner版本為12.5.0,但其有許多問題,alpine
新版映象在Kubernetes
中間斷髮生無法解析DNS
的問題,反映到GitLab-Runner
中就是Could not resolve host
和server misbehaving
查閱解決方法
通過查詢發現,其官方倉庫還有多個相關issue沒有關閉
官方gitlab:Kubernetes runner: Could not resolve host
stackoverflow:Gitlab Runner is not able to resolve DNS of Gitlab Server
給出的解決方案無一例外都是降級到alpine-v12.1.0
We had same issue for couple of days. We tried change CoreDNS config,move runners to different k8s cluster and so on. Finally today i checked my personal runner and found that i'm using different version. Runners in cluster had
gitlab/gitlab-runner:alpine-v12.3.0
,when mine hadgitlab/gitlab-runner:alpine-v12.0.1
. We added line
image: gitlab/gitlab-runner:alpine-v12.1.0 複製程式碼
in
values.yaml
and this solved problem for us
其問題的根源應該在於alpine基礎映象對Kubernetes 叢集支援有問題,
ndots breaks DNS resolving #64924
docker-alpine
倉庫對應也有未關閉的issue
,其中就提到了關於DNS
解析超時和異常的問題
安裝
一行命令安裝即可
$ helm install /root/gitlab-runner/ --name k8s-gitlab-runner --namespace gitlab-runner
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輸出如下
NAME: k8s-gitlab-runner
LAST DEPLOYED: Tue Nov 26 21:51:57 2019
NAMESPACE: gitlab-runner
STATUS: DEPLOYED
RESOURCES:
==> v1/ConfigMap
NAME DATA AGE
k8s-gitlab-runner-gitlab-runner 5 0s
==> v1/Deployment
NAME READY UP-TO-DATE AVAILABLE AGE
k8s-gitlab-runner-gitlab-runner 0/1 1 0 0s
==> v1/Pod(related)
NAME READY STATUS RESTARTS AGE
k8s-gitlab-runner-gitlab-runner-744d598997-xwh92 0/1 Pending 0 0s
==> v1/Role
NAME AGE
k8s-gitlab-runner-gitlab-runner 0s
==> v1/RoleBinding
NAME AGE
k8s-gitlab-runner-gitlab-runner 0s
==> v1/Secret
NAME TYPE DATA AGE
k8s-gitlab-runner-gitlab-runner Opaque 2 0s
==> v1/ServiceAccount
NAME SECRETS AGE
k8s-gitlab-runner-gitlab-runner 1 0s
NOTES:
Your GitLab Runner should now be registered against the GitLab instance reachable at: "https://gitlab.fjy8018.top/"
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檢視gitlab admin頁面,發現已經有一個runner成功註冊
工程配置
DinD方式構建所需配置
如果原本的ci
檔案是基於19.03 DinD
映象構建的則需要加上TLS
相關配置
image: docker:19.03
variables:
DOCKER_DRIVER: overlay
DOCKER_HOST: tcp://localhost:2375
DOCKER_TLS_CERTDIR: ""
...
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其餘配置保持不變,使用DinD構建
Kubectl和Kubernetes許可權配置
由於使用k8s
叢集,而通過叢集部署需要使用kubectl
客戶端,故手動建立了一個kubectl
docker
映象,使用gitlab
觸發dockerhub
構建,構建內容公開透明,可放心使用,如有其它版本的構建需求也可提pull request,會在後面補充,目前用到的只有1.14.0
有kubectl
客戶端,還需要配置連線TLS
和連線賬戶
為了保障安全,新建一個專門訪問該工程名稱空間的ServiceAccount
apiVersion: v1
kind: ServiceAccount
metadata:
name: hmdt-gitlab-ci
namespace: hmdt
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利用叢集提供的RBAC機制,為該賬戶授予該名稱空間的admin許可權
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: RoleBinding
metadata:
name: hmdt-gitlab-role
namespace: hmdt
subjects:
- kind: ServiceAccount
name: hmdt-gitlab-ci
namespace: hmdt
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: admin
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建立後在查詢其在k8s叢集中生成的唯一名稱,此處為hmdt-gitlab-ci-token-86n89
$ kubectl describe sa hmdt-gitlab-ci -n hmdt
Name: hmdt-gitlab-ci
Namespace: hmdt
Labels: <none>
Annotations: kubectl.`Kubernetes`.io/last-applied-configuration:
{"apiVersion":"v1","kind":"ServiceAccount","metadata":{"annotations":{},"name":"hmdt-gitlab-ci","namespace":"hmdt"}}
Image pull secrets: <none>
Mountable secrets: hmdt-gitlab-ci-token-86n89
Tokens: hmdt-gitlab-ci-token-86n89
Events: <none>
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然後根據上面的Secret找到CA證書
$ kubectl get secret hmdt-gitlab-ci-token-86n89 -n hmdt -o json | jq -r '.data["ca.crt"]' | base64 -d
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再找到對應的 Token
$ kubectl get secret hmdt-gitlab-ci-token-86n89 -n hmdt -o json | jq -r '.data.token' | base64 -d
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Kubernetes關聯GitLab配置
進入gitlab Kubernetes叢集配置頁面,填寫相關資訊,讓gitlab自動連線上叢集環境
注意,需要將此處取消勾選,否則gitlab會自動建立新的使用者賬戶,而不使用已經建立好的使用者賬戶,在執行過程中會報無許可權錯誤
不取消導致的報錯如下,gitlab建立了新的使用者賬戶hmdt-prod-service-account
,但沒有操作指定名稱空間的許可權
GitLab環境配置
建立環境
名稱和url可以按需自定義
CI指令碼配置
最終配置CI檔案如下,該檔案使用DinD
方式構建Dockerfile
image: docker:19.03
variables:
MAVEN_CLI_OPTS: "-s .m2/settings.xml --batch-mode -Dmaven.test.skip=true"
MAVEN_OPTS: "-Dmaven.repo.local=.m2/repository"
DOCKER_DRIVER: overlay
DOCKER_HOST: tcp://localhost:2375
DOCKER_TLS_CERTDIR: ""
SPRING_PROFILES_ACTIVE: docker
IMAGE_VERSION: "1.8.6"
DOCKER_REGISTRY_MIRROR: "https://XXX.mirror.aliyuncs.com"
stages:
- test
- package
- review
- deploy
maven-build:
image: maven:3-jdk-8
stage: test
retry: 2
script:
- mvn $MAVEN_CLI_OPTS clean package -U -B -T 2C
artifacts:
expire_in: 1 week
paths:
- target/*.jar
maven-scan:
stage: test
retry: 2
image: maven:3-jdk-8
script:
- mvn $MAVEN_CLI_OPTS verify sonar:sonar
maven-deploy:
stage: deploy
retry: 2
image: maven:3-jdk-8
script:
- mvn $MAVEN_CLI_OPTS deploy
docker-harbor-build:
image: docker:19.03
stage: package
retry: 2
services:
- name: docker:19.03-dind
alias: docker
before_script:
- docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" $CI_REGISTRY
script:
- docker build --pull -t "$CI_REGISTRY_IMAGE:$IMAGE_VERSION" .
- docker push "$CI_REGISTRY_IMAGE:$IMAGE_VERSION"
- docker logout $CI_REGISTRY
deploy_live:
image: fjy8018/kubectl:v1.14.0
stage: deploy
retry: 2
environment:
name: prod
url: https://XXXX
script:
- kubectl version
- kubectl get pods -n hmdt
- cd manifests/
- sed -i "s/__IMAGE_VERSION_SLUG__/${IMAGE_VERSION}/" deployment.yaml
- kubectl apply -f deployment.yaml
- kubectl rollout status -f deployment.yaml
- kubectl get pods -n hmdt
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若需要使用Kaniko
構建Dockerfile
,則配置如下
注意,其中依賴的映象gcr.io/kaniko-project/executor:debug
屬於谷歌映象倉庫,可能存在無法拉取的情況
image: docker:19.03
variables:
MAVEN_CLI_OPTS: "-s .m2/settings.xml --batch-mode -Dmaven.test.skip=true"
MAVEN_OPTS: "-Dmaven.repo.local=.m2/repository"
DOCKER_DRIVER: overlay
DOCKER_HOST: tcp://localhost:2375
DOCKER_TLS_CERTDIR: ""
SPRING_PROFILES_ACTIVE: docker
IMAGE_VERSION: "1.8.6"
DOCKER_REGISTRY_MIRROR: "https://XXX.mirror.aliyuncs.com"
cache:
paths:
- target/
stages:
- test
- package
- review
- deploy
maven-build:
image: maven:3-jdk-8
stage: test
retry: 2
script:
- mvn $MAVEN_CLI_OPTS clean package -U -B -T 2C
artifacts:
expire_in: 1 week
paths:
- target/*.jar
maven-scan:
stage: test
retry: 2
image: maven:3-jdk-8
script:
- mvn $MAVEN_CLI_OPTS verify sonar:sonar
maven-deploy:
stage: deploy
retry: 2
image: maven:3-jdk-8
script:
- mvn $MAVEN_CLI_OPTS deploy
docker-harbor-build:
stage: package
retry: 2
image:
name: gcr.io/kaniko-project/executor:debug
entrypoint: [""]
script:
- echo "{\"auths\":{\"$CI_REGISTRY\":{\"username\":\"$CI_REGISTRY_USER\",\"password\":\"$CI_REGISTRY_PASSWORD\"}}}" > /kaniko/.docker/config.json
- /kaniko/executor --context $CI_PROJECT_DIR --dockerfile $CI_PROJECT_DIR/Dockerfile --destination $CI_REGISTRY_IMAGE:$IMAGE_VERSION
deploy_live:
image: fjy8018/kubectl:v1.14.0
stage: deploy
retry: 2
environment:
name: prod
url: https://XXXX
script:
- kubectl version
- kubectl get pods -n hmdt
- cd manifests/
- sed -i "s/__IMAGE_VERSION_SLUG__/${IMAGE_VERSION}/" deployment.yaml
- kubectl apply -f deployment.yaml
- kubectl rollout status -f deployment.yaml
- kubectl get pods -n hmdt
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執行流水線
runner自動擴縮容
Kubernetes
中的runner會根據任務多少自動擴縮容,目前配置的上限為10個
Grafana也能監控到叢集在構建過程中的資源使用情況
使用DinD
構建Dockerfile
結果
使用Kaniko
構建Dockerfile
的結果
部署結果
執行部署時gitlab會自動注入配置好的kubectl
config
構建結果
部署完成後可在環境配置頁中檢視部署結果,只有成功的部署才會被記錄