directory search
Compose About versions and upgrading (Compose) ASP.NET Core + SQL Server on Linux (Compose) CLI environment variables (Compose) Command-line completion (Compose) Compose(组成) Compose command-line reference(组合命令行参考) Control startup order (Compose) Django and PostgreSQL (Compose) Docker stacks and distributed application bundles (Compose) docker-compose build(docker-compose构建) docker-compose bundle docker-compose config docker-compose create docker-compose down docker-compose events docker-compose exec docker-compose help docker-compose images docker-compose kill docker-compose logs docker-compose pause docker-compose port docker-compose ps docker-compose pull docker-compose push docker-compose restart docker-compose rm docker-compose run docker-compose scale docker-compose start docker-compose stop docker-compose top docker-compose unpause docker-compose up Environment file (Compose) Environment variables in Compose Extend services in Compose Frequently asked questions (Compose) Getting started (Compose) Install Compose Link environment variables (deprecated) (Compose) Networking in Compose Overview of Docker Compose Overview of docker-compose CLI Quickstart: Compose and WordPress Rails and PostgreSQL (Compose) Sample apps with Compose Using Compose in production Using Compose with Swarm Engine .NET Core application (Engine) About images, containers, and storage drivers (Engine) Add nodes to the swarm (Engine) Apply custom metadata (Engine) Apply rolling updates (Engine) apt-cacher-ng Best practices for writing Dockerfiles (Engine) Binaries (Engine) Bind container ports to the host (Engine) Breaking changes (Engine) Build your own bridge (Engine) Configure container DNS (Engine) Configure container DNS in user-defined networks (Engine) CouchDB (Engine) Create a base image (Engine) Create a swarm (Engine) Customize the docker0 bridge (Engine) Debian (Engine) Default bridge network Delete the service (Engine) Deploy a service (Engine) Deploy services to a swarm (Engine) Deprecated Engine features Docker container networking (Engine) Docker overview (Engine) Docker run reference (Engine) Dockerfile reference (Engine) Dockerize an application Drain a node (Engine) Engine FAQ (Engine) Fedora (Engine) Get started (Engine) Get started with macvlan network driver (Engine) Get started with multi-host networking (Engine) How nodes work (Engine) How services work (Engine) Image management (Engine) Inspect the service (Engine) Install Docker (Engine) IPv6 with Docker (Engine) Join nodes to a swarm (Engine) Legacy container links (Engine) Lock your swarm (Engine) Manage nodes in a swarm (Engine) Manage sensitive data with Docker secrets (Engine) Manage swarm security with PKI (Engine) Manage swarm service networks (Engine) Migrate to Engine 1.10 Optional Linux post-installation steps (Engine) Overview (Engine) PostgreSQL (Engine) Raft consensus in swarm mode (Engine) Riak (Engine) Run Docker Engine in swarm mode Scale the service (Engine) SDKs (Engine) Select a storage driver (Engine) Set up for the tutorial (Engine) SSHd (Engine) Storage driver overview (Engine) Store service configuration data (Engine) Swarm administration guide (Engine) Swarm mode key concepts (Engine) Swarm mode overlay network security model (Engine) Swarm mode overview (Engine) Understand container communication (Engine) Use multi-stage builds (Engine) Use swarm mode routing mesh (Engine) Use the AUFS storage driver (Engine) Use the Btrfs storage driver (Engine) Use the Device mapper storage driver (Engine) Use the OverlayFS storage driver (Engine) Use the VFS storage driver (Engine) Use the ZFS storage driver (Engine) Engine: Admin Guide Amazon CloudWatch logs logging driver (Engine) Bind mounts (Engine) Collect Docker metrics with Prometheus (Engine) Configuring and running Docker (Engine) Configuring logging drivers (Engine) Control and configure Docker with systemd (Engine) ETW logging driver (Engine) Fluentd logging driver (Engine) Format command and log output (Engine) Google Cloud logging driver (Engine) Graylog Extended Format (GELF) logging driver (Engine) Journald logging driver (Engine) JSON File logging driver (Engine) Keep containers alive during daemon downtime (Engine) Limit a container's resources (Engine) Link via an ambassador container (Engine) Log tags for logging driver (Engine) Logentries logging driver (Engine) PowerShell DSC usage (Engine) Prune unused Docker objects (Engine) Run multiple services in a container (Engine) Runtime metrics (Engine) Splunk logging driver (Engine) Start containers automatically (Engine) Storage overview (Engine) Syslog logging driver (Engine) tmpfs mounts Troubleshoot volume problems (Engine) Use a logging driver plugin (Engine) Using Ansible (Engine) Using Chef (Engine) Using Puppet (Engine) View a container's logs (Engine) Volumes (Engine) Engine: CLI Daemon CLI reference (dockerd) (Engine) docker docker attach docker build docker checkpoint docker checkpoint create docker checkpoint ls docker checkpoint rm docker commit docker config docker config create docker config inspect docker config ls docker config rm docker container docker container attach docker container commit docker container cp docker container create docker container diff docker container exec docker container export docker container inspect docker container kill docker container logs docker container ls docker container pause docker container port docker container prune docker container rename docker container restart docker container rm docker container run docker container start docker container stats docker container stop docker container top docker container unpause docker container update docker container wait docker cp docker create docker deploy docker diff docker events docker exec docker export docker history docker image docker image build docker image history docker image import docker image inspect docker image load docker image ls docker image prune docker image pull docker image push docker image rm docker image save docker image tag docker images docker import docker info docker inspect docker kill docker load docker login docker logout docker logs docker network docker network connect docker network create docker network disconnect docker network inspect docker network ls docker network prune docker network rm docker node docker node demote docker node inspect docker node ls docker node promote docker node ps docker node rm docker node update docker pause docker plugin docker plugin create docker plugin disable docker plugin enable docker plugin inspect docker plugin install docker plugin ls docker plugin push docker plugin rm docker plugin set docker plugin upgrade docker port docker ps docker pull docker push docker rename docker restart docker rm docker rmi docker run docker save docker search docker secret docker secret create docker secret inspect docker secret ls docker secret rm docker service docker service create docker service inspect docker service logs docker service ls docker service ps docker service rm docker service scale docker service update docker stack docker stack deploy docker stack ls docker stack ps docker stack rm docker stack services docker start docker stats docker stop docker swarm docker swarm ca docker swarm init docker swarm join docker swarm join-token docker swarm leave docker swarm unlock docker swarm unlock-key docker swarm update docker system docker system df docker system events docker system info docker system prune docker tag docker top docker unpause docker update docker version docker volume docker volume create docker volume inspect docker volume ls docker volume prune docker volume rm docker wait Use the Docker command line (Engine) Engine: Extend Access authorization plugin (Engine) Docker log driver plugins Docker network driver plugins (Engine) Extending Engine with plugins Managed plugin system (Engine) Plugin configuration (Engine) Plugins API (Engine) Volume plugins (Engine) Engine: Security AppArmor security profiles for Docker (Engine) Automation with content trust (Engine) Content trust in Docker (Engine) Delegations for content trust (Engine) Deploying Notary (Engine) Docker security (Engine) Docker security non-events (Engine) Isolate containers with a user namespace (Engine) Manage keys for content trust (Engine) Play in a content trust sandbox (Engine) Protect the Docker daemon socket (Engine) Seccomp security profiles for Docker (Engine) Secure Engine Use trusted images Using certificates for repository client verification (Engine) Engine: Tutorials Engine tutorials Network containers (Engine) Get Started Part 1: Orientation Part 2: Containers Part 3: Services Part 4: Swarms Part 5: Stacks Part 6: Deploy your app Machine Amazon Web Services (Machine) Digital Ocean (Machine) docker-machine active docker-machine config docker-machine create docker-machine env docker-machine help docker-machine inspect docker-machine ip docker-machine kill docker-machine ls docker-machine provision docker-machine regenerate-certs docker-machine restart docker-machine rm docker-machine scp docker-machine ssh docker-machine start docker-machine status docker-machine stop docker-machine upgrade docker-machine url Driver options and operating system defaults (Machine) Drivers overview (Machine) Exoscale (Machine) Generic (Machine) Get started with a local VM (Machine) Google Compute Engine (Machine) IBM Softlayer (Machine) Install Machine Machine Machine CLI overview Machine command-line completion Machine concepts and help Machine overview Microsoft Azure (Machine) Microsoft Hyper-V (Machine) Migrate from Boot2Docker to Machine OpenStack (Machine) Oracle VirtualBox (Machine) Provision AWS EC2 instances (Machine) Provision Digital Ocean Droplets (Machine) Provision hosts in the cloud (Machine) Rackspace (Machine) VMware Fusion (Machine) VMware vCloud Air (Machine) VMware vSphere (Machine) Notary Client configuration (Notary) Common Server and signer configurations (Notary) Getting started with Notary Notary changelog Notary configuration files Running a Notary service Server configuration (Notary) Signer configuration (Notary) Understand the service architecture (Notary) Use the Notary client
characters

您可以使用depends_on选项来控制服务启动的顺序。撰写总是依赖顺序,其中依赖性是通过确定启动容器depends_onlinksvolumes_from,和network_mode: "service:..."

但是,Compose不会等到容器“准备就绪”(无论对于您的特定应用程序而言意味着什么) - 直到它运行为止。这有一个很好的理由。

等待数据库(例如)准备就绪的问题实际上只是分布式系统的一个更大问题的一个子集。在生产中,您的数据库可能随时无法使用或移动主机。您的应用程序需要适应这些类型的故障。

为了处理这个问题,应用程序应该尝试在失败后重新建立到数据库的连接。如果应用程序重试连接,它应该最终能够连接到数据库。

最好的解决方案是在你的应用程序代码中执行这个检查,无论是在启动时,还是因任何原因丢失连接。但是,如果您不需要此级别的恢复能力,则可以使用包装脚本解决该问题:

  • 使用一个工具,如等待,dockerize或sh兼容等待。这些小包装脚本可以包含在应用程序的映像中,并将轮询给定的主机和端口,直到它接受TCP连接。例如,要使用wait-for-it.shwait-for包装服务的命令:version:“2”services:web:build:。端口: - “80:8000”depends_on: - “db”命令:“./wait-for-it.sh”,“db:5432”,“ - ”,“python”,“app.py”db: image:postgres   提示:这种第一种解决方案存在局限性; 例如,它不会验证特定服务何时准备就绪。如果您为命令添加更多参数,bash shift 带循环的命令,如下一个示例所示。

  • 或者,编写自己的包装脚本以执行更多特定于应用程序的运行状况检查。例如,您可能要等到Postgres完全准备好接受命令:#!/ bin / bash#wait-for-postgres.sh set -e host =“$ 1”shift cmd =“$ @”,直到psql -h “$ host”-U“postgres”-c'\ l'; do>&2 echo“Postgres is unavailable  -  sleeping”sleep 1 done>&2 echo“Postgres正在执行 - 执行命令”exec $ cmd您可以像上例那样使用它作为包装脚本,方法是:command:“./ wait-for-postgres.sh“,”db“,”python“,”app.py“

Previous article: Next article: