在创建 docker 服务时检测到某些图像的任务失败

Question

我正在尝试创建 docker swarm 服务，但出现了一些奇怪的行为：

对于某些图像，它是成功的，对于某些图像，我收到错误消息：

docker service create nginx 89t21k3udf007pvl2ucvmdp9l overall progress: 1 out of 1 tasks 1/1: running [==================================================>] verify: Service converged --> 成功

docker service create hello-world 8hhdki32ypfwshh2wvijkkmvb overall progress: 0 out of 1 tasks 1/1: preparing [=================================> ] verify: Detected task failure --> 失败

供您参考：docker pull hello-world工作正常。

我的印象是我们可以为所有图像创建服务，是否有任何条款和条件？我错过了什么吗？

注意：这是基本部分，但我的主要目的是为本地注册表镜像创建服务。但是在调试的第一步中发现了问题，即hello-world。

Answer 1

它失败是因为从 hello-world Docker 镜像创建的容器只显示一条消息然后退出，而且这种情况很快就会发生。

并且由于您创建了一个 swarm 服务，它会在每次失败时继续重新创建容器，这是意料之中的，这就是服务似乎失败的原因。

请看下面的服务日志，你会看到容器不断被重新创建：

[ ~]$ docker service create --name helloworld hello-world iilsd1yc706zgcdg35l8sdz3z
Since --detach=false was not specified, tasks will be created in the background.
In a future release, --detach=false will become the default.

[ ~]$ docker service logs helloworld  -f
helloworld.1.jxxnqzximfy7@    |
helloworld.1.zwyhf6x4cpdm@    |
helloworld.1.jxxnqzximfy7@    | Hello from Docker!
helloworld.1.zwyhf6x4cpdm@    | Hello from Docker!
helloworld.1.jxxnqzximfy7@    | This message shows that your installation appears to be working correctly.
helloworld.1.zwyhf6x4cpdm@    | This message shows that your installation appears to be working correctly.
helloworld.1.zwyhf6x4cpdm@   |
helloworld.1.jxxnqzximfy7@    |
helloworld.1.jxxnqzximfy7@    | To generate this message, Docker took the following steps:
helloworld.1.zwyhf6x4cpdm@    | To generate this message, Docker took the following steps:
helloworld.1.zwyhf6x4cpdm@    |  1. The Docker client contacted the Docker daemon.
helloworld.1.jxxnqzximfy7@    |  1. The Docker client contacted the Docker daemon.
helloworld.1.jxxnqzximfy7@    |  2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
helloworld.1.zwyhf6x4cpdm@    |  2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
helloworld.1.zwyhf6x4cpdm@    |     (amd64)
helloworld.1.jxxnqzximfy7@    |     (amd64)
helloworld.1.zwyhf6x4cpdm@   |  3. The Docker daemon created a new container from that image which runs the
helloworld.1.jxxnqzximfy7@    |  3. The Docker daemon created a new container from that image which runs the
helloworld.1.jxxnqzximfy7@    |     executable that produces the output you are currently reading.
helloworld.1.zwyhf6x4cpdm@    |     executable that produces the output you are currently reading.
helloworld.1.zwyhf6x4cpdm@    |  4. The Docker daemon streamed that output to the Docker client, which sent it
helloworld.1.jxxnqzximfy7@    |  4. The Docker daemon streamed that output to the Docker client, which sent it
helloworld.1.jxxnqzximfy7@    |     to your terminal.
helloworld.1.zwyhf6x4cpdm@    |     to your terminal.
helloworld.1.jxxnqzximfy7@    |
helloworld.1.jxxnqzximfy7@    | To try something more ambitious, you can run an Ubuntu container with:
helloworld.1.zwyhf6x4cpdm@    |
helloworld.1.zwyhf6x4cpdm@    | To try something more ambitious, you can run an Ubuntu container with:
helloworld.1.jxxnqzximfy7@    |  $ docker run -it ubuntu bash
helloworld.1.jxxnqzximfy7@    |
helloworld.1.zwyhf6x4cpdm@    |  $ docker run -it ubuntu bash
helloworld.1.jxxnqzximfy7@    | Share images, automate workflows, and more with a free Docker ID:
helloworld.1.jxxnqzximfy7@    |  https://hub.docker.com/
helloworld.1.zwyhf6x4cpdm@    |
helloworld.1.zwyhf6x4cpdm@    | Share images, automate workflows, and more with a free Docker ID:
helloworld.1.jxxnqzximfy7@    |
helloworld.1.zwyhf6x4cpdm@    |  https://hub.docker.com/
helloworld.1.zwyhf6x4cpdm@    |
helloworld.1.jxxnqzximfy7@    | For more examples and ideas, visit:
helloworld.1.jxxnqzximfy7@    |  https://docs.docker.com/get-started/
helloworld.1.zwyhf6x4cpdm@    | For more examples and ideas, visit:
helloworld.1.jxxnqzximfy7@    |
helloworld.1.zwyhf6x4cpdm@    |  https://docs.docker.com/get-started/
helloworld.1.zwyhf6x4cpdm@    |
helloworld.1.yw17ktyymrp6@    |
helloworld.1.yw17ktyymrp6@    | Hello from Docker!
helloworld.1.yw17ktyymrp6@    | This message shows that your installation appears to be working correctly.

您应该尝试使用不同的 Docker 映像，busybox例如：

[~]$ docker service create --name helloworld busybox:latest sh -c "while true; do echo Hello; sleep 2; done"
yjxzteshp7k2xf4aznj4l86s6
Since --detach=false was not specified, tasks will be created in the background.
In a future release, --detach=false will become the default.
[~]$ docker service ps helloworld --no-trunc
ID                          NAME                IMAGE                                                                                    NODE                              DESIRED STATE       CURRENT STATE          ERROR               PORTS
33xe78ekfjkmti8yahrcp5gug   helloworld.1        busybox:latest@sha256:2a03a6059f21e150ae84b0973863609494aad70f0a80eaeb64bddd8d92465812      Running             Running 1 second ago
[~]$ docker service logs -f helloworld
helloworld.1.33xe78ekfjkm@    | Hello
helloworld.1.33xe78ekfjkm@    | Hello
helloworld.1.33xe78ekfjkm@    | Hello
helloworld.1.33xe78ekfjkm@    | Hello
helloworld.1.33xe78ekfjkm@    | Hello
^C