在Windows 10中使用docker-compose时，不会在Scylla中创建卷 [英] Volume isn't created in Scylla when using docker-compose in Windows 10

问题描述

我刚刚开始学习Docker和docker-compose，我想尝试ScyllaDB(数据库).我想通过带有持久性存储的docker-compose在Docker中启动ScyllaDB的单个实例.永久性存储应保存在相对于我的docker-compose文件的文件夹'target'中.问题是我看不到正在创建任何文件夹，但是docker-compose似乎可以保留数据，但是我不确定在哪里可以找到ScyllaDB创建的文件.循序渐进的再现路径:

I just started learning Docker and docker-compose and I want to try out ScyllaDB (database). I want to start a single instance of ScyllaDB in Docker through docker-compose with persistent storage. The persistent storage should be saved in folder 'target' relative to my docker-compose file. The problem is that I don't see any folder being created, but docker-compose seems to persist the data, but I am not sure where I can locate the files that ScyllaDB created. Step by step reproduction path:

1. 使用以下内容创建一个docker-compose.yml(/var/lib/scylla应该根据 docker-compose.yml

   version: '3'
   
   services:
     b-scylla:
       image: "scylladb/scylla:4.3.1"
       container_name: b-scylla
       volumes:
         - ./target:/var/lib/scylla
       ports:
         - "127.0.0.1:9042:9042"
         - "127.0.0.1:9160:9160"
   

   1. 这不会产生任何结果: $ docker volume ls
   2. 启动docker-compose并等待一分钟，以便ScyllaDB启动: $ docker-compose up -d
   3. 这仍然没有任何结果: $ docker volume ls .我希望Docker应该创建一个卷(./target/).
   4. 在ScyllaDB中保留一些数据以验证数据是否保存在某处:
   1. This does not give any result: $ docker volume ls
   2. Start up docker-compose and wait a minute for ScyllaDB to start up: $ docker-compose up -d
   3. This does still not give any result: $ docker volume ls. I expect that Docker should created a volume (./target/).
   4. Persist some data in ScyllaDB to verify that the data is saved somewhere:

   运行以下命令:

   $ docker exec -it b-scylla cqlsh
   $ create keyspace somekeyspace with replication = {
       'class': 'NetworkTopologyStrategy',
       'replication_factor': 2
   };
   

   1. 创建的键空间保存在某个地方，但我不知道在哪里.我希望它只是在目标文件夹中，但是甚至没有创建该文件夹.当我重新启动docker-compose时，键空间仍然存在，因此数据保存在某个地方，但是在哪里?

   推荐答案

   您正在使用短语法"；用于数据挂载( https://docs.docker.com/compose/compose-file/compose-file-v3/#short-syntax-3 )正在创建绑定挂载点.绑定不是卷.无法使用 docker volume ls 检查它们.您可以使用 docker inspect {container} 了解有关您的挂载的信息.

   You are using the "short syntax" for data mounting (https://docs.docker.com/compose/compose-file/compose-file-v3/#short-syntax-3) that is creating a mount point binding. Bindings are not volumes. They can't be checked with the docker volume ls. You can find out about your mounts with docker inspect {container}.

   但是，在绑定安装后，Scylla图像对我而言无法正确启动.我看到了在安装目录中写入sstables时出现的恒定文件系统错误:

   However, Scylla image does not start for me correctly with the bind mounting. I saw constant file system errors for writing sstables in mounted directory:

   version: '3'
   
   services:
     b-scylla:
       image: "scylladb/scylla:4.3.1"
       container_name: b-scylla
       volumes:
         - ./target:/var/lib/scylla
   

   $  docker compose up -f .\test.yaml
   

   b-scylla    | INFO  2021-03-04 07:24:53,132 [shard 0] init - initializing batchlog manager
   b-scylla    | INFO  2021-03-04 07:24:53,135 [shard 0] legacy_schema_migrator - Moving 0 keyspaces from legacy schema tables to the new schema keyspace (system_schema)
   b-scylla    | INFO  2021-03-04 07:24:53,136 [shard 0] legacy_schema_migrator - Dropping legacy schema tables
   b-scylla    | ERROR 2021-03-04 07:24:53,168 [shard 0] table - failed to write sstable /var/lib/scylla/data/system/truncated-38c19fd0fb863310a4b70d0cc66628aa/mc-8-big-Data.db: std::system_error (error system:2, No such file or directory)
   

   我没有找到导致这种情况的原因，但是该目录是可写的，并且包含大多数正常的初始数据-保留的commitlog段和system ks数据文件夹.

   I did not find out what causes this, but the dir is writable and contains most of the normal initial data - reserved commitlog segments and system ks data folders.

   实际有效的方法是使用卷

   What actually works is using Volumes:

   version: '3'
   
   services:
     b-scylla:
       image: "scylladb/scylla:4.3.1"
       container_name: b-scylla
       volumes:
         - type: volume
           source: target
           target: /var/lib/scylla
           volume:
             nocopy: true
             
   volumes:
     target:
   

   $  docker compose up -f .\test.yaml
   

   $ docker volume ls
   DRIVER    VOLUME NAME
   local     6b57922b3380d61b960110dacf8d180e663b1ce120494d7a005fc08cee475234
   local     ad220954e311ea4503eb3179de0d1162d2e75b73d1d9582605b4e5c0da37502d
   local     projects_target
   
   $ docker volume inspect projects_target
   [
       {
           "CreatedAt": "2021-03-04T07:20:40Z",
           "Driver": "local",
           "Labels": {
               "com.docker.compose.project": "projects",
               "com.docker.compose.version": "1.0-alpha",
               "com.docker.compose.volume": "target"
           },
           "Mountpoint": "/var/lib/docker/volumes/projects_target/_data",
           "Name": "projects_target",
           "Options": null,
           "Scope": "local"
       }
   ]
   

   Scylla在此模式下成功启动.

   And Scylla starts successfully in this mode.

   您当然可以使用以下方法将此卷安装到任何其他容器上:

   You of course can mount this volume to any other container with:

   $ docker run -it --mount source=projects_target,target=/app --entrypoint bash scylladb/scylla:4.3.1
   

   或通过WSL访问它(在Docker桌面(Windows)中定位数据卷):

   or accessing it via WSL (Locating data volumes in Docker Desktop (Windows)):

   $ \\wsl$\docker-desktop-data\version-pack-data\community\docker\volumes\projects_target\_data
   

   这篇关于在Windows 10中使用docker-compose时，不会在Scylla中创建卷的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！