在CentOS上配置GitLab CI/CD，可按以下步骤进行：

安装GitLab

添加GitLab仓库：curl -sS https://packages.gitlab.com/install/repositories/gitlab/gitlab-ce/script.rpm.sh | sudo bash。安装GitLab CE：sudo yum install -y gitlab-ce。启动并启用GitLab服务：sudo systemctl start gitlab，sudo systemctl enable gitlab。访问http://完成初始设置。

配置GitLab Runner

安装Runner：curl -L https://packages.gitlab.com/install/repositories/runner/gitlab-runner/script.rpm.sh | sudo bash，sudo yum install gitlab-runner。注册Runner：在GitLab项目页面的Settings -> CI/CD -> Runners中，点击New Runner，按提示输入URL、注册令牌等信息，选择执行器类型（如Shell或Docker）。以Shell执行器为例，注册命令为sudo gitlab-runner register --non-interactive --url "http://your_gitlab_instance" --registration-token "your_token" --executor "shell" --description "your_runner_description"。

创建.gitlab-ci.yml文件

在项目根目录下创建该文件，定义CI/CD流程。例如：

stages:
  - build
  - test
  - deploy
build_job:
  stage: build
  script:
    - echo "Building the project..."
test_job:
  stage: test
  script:
    - echo "Running tests..."
deploy_job:
  stage: deploy
  script:
    - echo "Deploying the project..."
  only:
    - master

提交代码触发流程

将.gitlab-ci.yml文件提交到GitLab仓库并推送，GitLab Runner会自动检测并执行配置的流水线任务。可在GitLab的CI/CD -> Pipelines页面查看执行状态和日志。