openshift/origin工作記錄（1）——S2I鏡像定製(基於SVN)

本篇博客所用到的代碼已上傳至github。https://github.com/hu12081/openshift-s2i-tomcat-svn.git
不建議直接clone git，否則，注意修改文件權限。

s2i源碼研究（能力不夠，修改失敗）

週一的時候在github上粗略閱讀了source-to-image的源碼，代碼地址爲https://github.com/openshift/source-to-image。整體代碼採用go語言實現，https://github.com/openshift/source-to-image/tree/master/pkg/scm/downloaders目錄下的代碼應該是實現代碼下載功能的，包括從本地文件路徑拷貝代碼、通過git克隆代碼。

修改builder鏡像，定製部署模板（成功實現）

週二在看《開源容器雲openshift》一書時，無意在書中發現作者的github，上面就有svn的demo，地址爲https://github.com/nichochen/openshift-tomcat-svn。着實尷尬。

該項目的最後提交時間爲兩年前，在嘗試部署的過程中發現存在以下問題：

1.ose-json文件夾下的openshift-tomcat7-svn-is.json存在語法錯誤。
2.該部署模板雖然集成了svn，但是在web界面上必須填寫可用的git地址（該地址只用於跳過s2i驗證），作者在README.md指出了該缺陷，缺沒有修復。
3.沒有提供svn的賬號、密碼輸入功能。
4.直接clone該項目，在builder鏡像的使用過程中，會報文件夾權限的問題。

優化已有的開源項目

參考我的博客openshift/origin學習記錄（9）——S2I鏡像定製(基於Git)
以下內容有做了一些定製化開發（基本都有表明）不具有通用性，不推薦直接複製粘貼使用！！！請自行修改參數、指令等內容。

創建S2I Builder鏡像工作目錄

通過s2i create命令創建一個名爲tomcat-s2i的S2I Builder鏡像。第二個參數tomcat-svn爲S2I Builder鏡像名稱。第三個參數tomcat-svn-catalog定義了工作目錄的名稱。

s2i create tomcat-svn tomcat-svn-catalog

編寫Dockerfile

修改tomcat-svn-catalog目錄下的Dockerfile文件。

# openshift-tomcat8-svn
FROM docker.io/centos
# TODO: Put the maintainer name in the image metadata
MAINTAINER huliaoliao
# TODO: Rename the builder environment variable to inform users about application you provide them
ENV BUILDER_VERSION 1.0
# TODO: Set labels used in OpenShift to describe the builder image
LABEL io.openshift.s2i.scripts-url=image:///usr/libexec/s2i \
      io.k8s.description="Platform for building tomcat" \
      io.k8s.display-name="builder tomcat" \
      io.openshift.expose-services="8080:http" \
      io.openshift.tags="builder,tomcat,java,etc."
# TODO: Install required packages here:
COPY ./CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo
RUN yum makecache &&  yum install -y java-1.8.0-openjdk subversion maven && yum clean all -y
COPY ./s2i/bin/ /usr/libexec/s2i
# TODO (optional): Copy the builder files into /opt/app-root
COPY ./tomcat8/ /opt/app-root/tomcat8
# TODO: Copy the S2I scripts to /usr/local/s2i, since openshift/base-centos7 image sets io.openshift.s2i.scripts-url label that way, or update that label
#COPY ./s2i/bin/ /usr/libexec/s2i
# TODO: Drop the root user and make the content of /opt/app-root owned by user 1001
RUN useradd -m tomcat -u 1002 && \
    chmod -R a+rw /opt && \
    chmod -R a+rw /opt/app-root && \
    chmod a+rwx /opt/app-root/tomcat8/* && \
    chmod +x /opt/app-root/tomcat8/bin/*.sh && \
    rm -rf /opt/app-root/tomcat8/webapps/* && \
    rm -rf /usr/share/maven/conf/settings.xml
ADD ./settings.xml /usr/share/maven/conf/
# This default user is created in the openshift/base-centos7 image
USER 1002
# TODO: Set the default port for applications built using this image
EXPOSE 8080
ENTRYPOINT []
# TODO: Set the default CMD for the image
CMD ["/usr/libexec/s2i/usage"]

其中COPY ./CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo是爲了換源。rm -rf /usr/share/maven/conf/settings.xml和ADD ./settings.xml /usr/share/maven/conf/是修改鏡像中maven的配置，指向自己的maven庫。

下載tomcat

wget http://archive.apache.org/dist/tomcat/tomcat-8/v8.5.5/bin/apache-tomcat-8.5.5.tar.gz

解壓到tomcat-svn-catalog目錄下的tomcat8文件夾下。

修改s2i/bin/assemble腳本（負責源代碼的編譯、構建以及構建產出物的部署）

#!/bin/bash -e
#
# S2I assemble script for the 'nico-tomcat' image.
# The 'assemble' script builds your application source ready to run.
#
# For more information refer to the documentation:
#       https://github.com/openshift/source-to-image/blob/master/docs/builder_image.md
#
# Restore artifacts from the previous build (if they exist).
#
if [ "$1" = "-h" ]; then
        # If the 'nico-tomcat' assemble script is executed with '-h' flag,
        # print the usage.
        exec /usr/libexec/s2i/usage
fi
# Restore artifacts from the previous build (if they exist).
#
if [ "$(ls /tmp/artifacts/ 2>/dev/null)" ]; then
  echo "---> Restoring build artifacts"
  mv /tmp/artifacts/. ./
fi
echo "---> Installing application source"
WORK_DIR=/tmp/src;
cd $WORK_DIR;
if [ ! -z ${SVN_URI} ] ; then
  echo "Fetching source from Subversion repository ${SVN_URI}"
  svn co ${SVN_URI} --username=${SVN_USERNAME} --password=${SVN_PASSWORD} --no-auth-cache
  export SRC_DIR=`basename $SVN_URI`
  echo "Finished fetching source from Subversion repository ${SVN_URI}"
  cd $WORK_DIR/$SRC_DIR/
  mvn package -Dmaven.test.skip=true;
else
  echo "SVN_URI not set, skip Subverion source download";
fi
find /tmp/src/ -name '*.war'|xargs -i mv -v {} /opt/app-root/tomcat8/webapps/ROOT.war
echo "---> Building application from source"

文件中下面這句就是根據用戶輸入的svn路徑、賬號、密碼下載代碼。

 svn co ${SVN_URI} --username=${SVN_USERNAME} --password=${SVN_PASSWORD} --no-auth-cache

編輯s2i/bin/run腳本（S2I流程生成的最終鏡像將以這個腳本作爲容器的啓動命令）。

腳本內容爲啓動tomcat。

#!/bin/bash -e
#
# S2I run script for the 'nico-tomcat' image.
# The run script executes the server that runs your application.
#
# For more information see the documentation:
#       https://github.com/openshift/source-to-image/blob/master/docs/builder_image.md
#
exec /opt/app-root/tomcat8/bin/catalina.sh run

構建鏡像並推送到自己的鏡像倉庫

在tomcat-svn-catalog目錄下執行make。得到docker鏡像後修改tag推送到鏡像倉庫。

在master節點上創建openshift-tomcat8-svn-is.json文件

{
  "kind": "ImageStreamList",
  "apiVersion": "v1",
  "metadata": {},
  "items": [
    {
      "kind": "ImageStream",
      "apiVersion": "v1",
      "metadata": {
        "name": "openshift-tomcat8-svn",
        "annotations": {"openshift.io/image.insecureRepository": "true"},
        "creationTimestamp": null
      },
      "spec": {
        "dockerImageRepository": "master.example.com:5000/openshift-tomcat8-svn",
        "tags": [
          {
            "name": "latest"
          },
          {
            "name": "2.0",
            "annotations": {
              "description": "Run JavaEE WAR applications",
              "iconClass": "icon-ruby",
              "tags": "builder,tomcat,java,war",
              "supports": "java",
              "version": "1.0"
            },
            "from": {
              "kind": "ImageStreamTag",
              "name": "latest"
            }
          }
        ]
      }
    }  ]
}

集羣管理員賬號執行命令。

oc create -n openshift -f openshift-tomcat8-svn-is.json

在master節點上創建openshift-tomcat8-svn-removegit-template.json文件

{
    "kind": "Template",
    "apiVersion": "v1",
    "metadata": {
        "annotations": {
            "iconClass" : "icon-tomcat",
            "description": "Application template for JavaEE WAR deployment with Tomcat 8."
        },
        "name": "openshift-tomcat8-svn-removegit"
    },
    "labels": {
        "template": "openshift-tomcat8-svn-removegit"
    },
    "parameters": [
        {
            "description": "Tomcat 8.5.5",
            "name": "IMG_VERSION",
            "displayName":"Image Version",
            "value": "latest",
            "required": true
        },
        {
            "description": "The name for the application.",
            "name": "APPLICATION_NAME",
            "displayName":"Application Name",
            "value": "",
            "required": true
        },
        {
            "description": "Custom hostname for service routes.  Leave blank for default hostname, e.g.: <application-name>.<project>.<default-domain-suffix>",
            "name": "APPLICATION_HOSTNAME",
            "displayName":"Application Hostname",
            "value": ""
        },
        {
            "description": "Subversion source URI for application",
            "name": "SVN_URI",
            "displayName":"Subversion source URI",
            "value": "",
            "required": true
        },
        {
            "description": "Subversion Username",
            "name": "SVN_USERNAME",
            "displayName":"Subversion Username",
            "value": "",
            "required": true
        },
        {
            "description": "Subversion Password",
            "name": "SVN_PASSWORD",
            "displayName":"Subversion Password",
            "value": "",
            "required": true
        }
    ],
    "objects": [
        {
            "kind": "Service",
            "apiVersion": "v1",
            "spec": {
                "ports": [
                    {
                        "port": 8080,
                        "targetPort": 8080
                    }
                ],
                "selector": {
                    "deploymentConfig": "${APPLICATION_NAME}"
                }
            },
            "metadata": {
                "name": "${APPLICATION_NAME}",
                "labels": {
                    "application": "${APPLICATION_NAME}"
                },
                "annotations": {
                    "description": "The web server's http port."
                }
            }
        },
        {
            "kind": "Route",
            "apiVersion": "v1",
            "id": "${APPLICATION_NAME}-http-route",
            "metadata": {
                "name": "${APPLICATION_NAME}-http-route",
                "labels": {
                    "application": "${APPLICATION_NAME}"
                },
                "annotations": {
                    "description": "Route for application's http service."
                }
            },
            "spec": {
                "host": "${APPLICATION_HOSTNAME}",
                "to": {
                    "name": "${APPLICATION_NAME}"
                }
            }
        },
        {
            "kind": "ImageStream",
            "apiVersion": "v1",
            "metadata": {
                "name": "${APPLICATION_NAME}",
                "labels": {
                    "application": "${APPLICATION_NAME}"
                }
            }
        },
        {
            "kind": "BuildConfig",
            "apiVersion": "v1",
            "metadata": {
                "name": "${APPLICATION_NAME}",
                "labels": {
                    "application": "${APPLICATION_NAME}"
                }
            },
            "spec": {
                "strategy": {
                    "type": "Source",
                    "sourceStrategy": {
                        "from": {
                            "kind": "ImageStreamTag",
                            "namespace": "openshift",
                            "name": "openshift-tomcat8-svn:latest"
                        },
                        "env": [
                                    {
                                        "name": "SVN_URI",
                                        "value": "${SVN_URI}"
                                    },
                                    {
                                        "name": "SVN_USERNAME",
                                        "value": "${SVN_USERNAME}"
                                    },
                                    {
                                        "name": "SVN_PASSWORD",
                                        "value": "${SVN_PASSWORD}"
                                    }

                       ]
                    }
                },
                "output": {
                    "to": {
                        "kind": "ImageStreamTag",
                        "name": "${APPLICATION_NAME}:latest"
                    }
                },
                "triggers": [
                    {
                        "type": "GitHub",
                        "github": {
                            "secret": "${GITHUB_TRIGGER_SECRET}"
                        }
                    },
                    {
                        "type": "Generic",
                        "generic": {
                            "secret": "${GENERIC_TRIGGER_SECRET}"
                        }
                    },
                    {
                        "type": "ImageChange",
                        "imageChange": {}
                    }
                ]
            }
        },
        {
            "kind": "DeploymentConfig",
            "apiVersion": "v1",
            "metadata": {
                "name": "${APPLICATION_NAME}",
                "labels": {
                    "application": "${APPLICATION_NAME}"
                }
            },
            "spec": {
                "strategy": {
                    "type": "Recreate"
                },
                "triggers": [
                    {
                        "type": "ImageChange",
                        "imageChangeParams": {
                            "automatic": true,
                            "containerNames": [
                                "${APPLICATION_NAME}"
                            ],
                            "from": {
                                "kind": "ImageStream",
                                "name": "${APPLICATION_NAME}"
                            }
                        }
                    }
                ],
                "replicas": 1,
                "selector": {
                    "deploymentConfig": "${APPLICATION_NAME}"
                },
                "template": {
                    "metadata": {
                        "name": "${APPLICATION_NAME}",
                        "labels": {
                            "deploymentConfig": "${APPLICATION_NAME}",
                            "application": "${APPLICATION_NAME}"
                        }
                    },
                    "spec": {
                        "containers": [
                            {
                                "name": "${APPLICATION_NAME}",
                                "image": "${APPLICATION_NAME}",
                                "imagePullPolicy": "Always",
                                "readinessProbe": {
                                    "exec": {
                                        "command": [
                                            "/bin/bash",
                                            "-c",
                                            "curl http://localhost:8080"
                                        ]
                                    }
                                },
                                "ports": [
                                    {
                                        "name": "http",
                                        "containerPort": 8080,
                                        "protocol": "TCP"
                                    }
                                ],
                                "env": [
                                    {
                                        "name": "SVN_URI",
                                        "value": "${SVN_URI}"
                                    }

                                ]
                            }
                        ]
                    }
                }
            }
        }
    ]
}

集羣管理員賬號執行命令。

oc create -n openshift -f openshift-tomcat8-svn-removegit-template.json

驗證

可從界面輸入SVN的地址、賬號、密碼完成創建。

最終完成了從SVN拉取代碼、編譯、部署等一系列流程。

已知缺陷

1.SVN密碼現在是明文的形式
2.template中暫未提供對build config、deploy config等的配置，界面還較爲簡單。

結語

本篇博客主要記錄了工作過程，沒有特別具體，但基本覆蓋了所有過程。

僅供參考。