当我docker-compose pull为一个有很多服务的项目运行时，我看到这样的输出：
...
Pulling service1 ... downloading (64.0%)
Pulling service2 ... downloading (79.3%)
Pulling service3 ... downloading (64.0%)
...
这些数字似乎有涨有跌，有时它们会同时针对多种服务进行更新。这个输出是什么意思，如何理解实际进度docker-compose pull？
Actually my experience has been that docker-compose just doesn't handle the docker layer correctly.
If you run docker inspect you'll get a list of 'Layers' when you do a docker-compose pull it fetches each of them respectively.
If you run:
docker pull ubuntu:latest
You'll get an output like this:
latest: Pulling from library/ubuntu
a4a2a29f9ba4: Pull complete
127c9761dcba: Pull complete
d13bf203e905: Pull complete
4039240d2e0b: Pull complete
Digest: sha256:35c4a2c15539c6c1e4e5fa4e554dac323ad0107d8eb5c582d6ff386b383b7dce
Status: Downloaded newer image for ubuntu:latest
docker.io/library/ubuntu:latest
You'll notice that there were 4 Layers that were pulled, downloaded, and extracted.
When I run docker-compose pull, assuming it needs to pull all 4 layers again, the % status just goes haywire since it's showing you the status of a specific layer, and once it's done it'll show you the status of the next one to download.
ie.
Docker:
layer1: 50%
layer2: 70%
docker-compose output: 50%
once docker status is:
layer1: 100%
layer2: 80%
docker-compose output: 80% (ie. i drops down from 100% to 80% since there is another layer downloading)
That being said, it's a bad user pattern and confusing but I believe that's what's going on under the hood. An actual docker-compose dev can correct me if i'm wrong.
大多数撰写文件中都有多个服务。通常这些服务不是从本地 Dockerfile 构建的，而是引用远程存储库中的图像。每个服务由多个图像层组成。
默认情况下，adocker-compose pull将并行更新所有服务（有关更多信息，请参阅官方文档）。该百分比适用于该服务中正在下载和更新的特定层。因为一个图像可以有许多不同大小的层，所以当你使用这个命令时这个数字可能会波动。
它正在检索您的 docker-compose 文件服务中指定的各种 docker 映像。如果可以的话，它将为每个服务并行拉多个层，因此您可以看到每个服务的一些不同进展。