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get-started: fix/simplify the persisting data experiment 

Signed-off-by: David Karlsson <35727626+dvdksn@users.noreply.github.com>
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David Karlsson 2024-10-31 16:50:13 +01:00
parent 158beace56
commit 47ffcff13d
1 changed files with 16 additions and 22 deletions
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content/get-started/workshop/05_persisting_data.md
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@ -21,43 +21,37 @@ changes won't be seen in another container, even if they're using the same image
### See this in practice ### See this in practice
To see this in action, you're going to start two containers. In one container, you'll create a file. In the other container, you'll verify the file exists. To see this in action, you're going to start two containers. In one container,
What you'll see is that the file created in one container isn't available in another. you'll create a file. In the other container, you'll check whether that same
file exists.
1. Start an Alpine container and access its shell. 1. Start an Alpine container and create a new file in it.
```console ```console
$ docker run -ti --name=mytest alpine $ docker run --rm alpine touch greeting.txt
``` ```
2. In the container, create a `greeting.txt` file with `hello` inside. > [!TIP]
> Any commands you specify after the image name (in this case, `alpine`)
> are executed inside the container. In this case, the command `touch
> greeting.txt` puts a file named `greeting.txt` on the container's filesystem.
```console 2. Run a new Alpine container and use the `stat` command to check whether the file exists.
/ # echo "hello" > greeting.txt
```
3. Exit the container.
```console
/ # exit
```
4. Run a new Alpine container and use the `cat` command to verify that the
file does not exist.
```console ```console
$ docker run alpine cat greeting.txt $ docker run --rm alpine stat greeting.txt
``` ```
You should see output similar to the following that indicates the file does not exist in the new container. You should see output similar to the following that indicates the file does not exist in the new container.
```console ```console
cat: can't open 'greeting.txt': No such file or directory stat: can't stat 'greeting.txt': No such file or directory
``` ```
5. Go ahead and remove the containers using `docker ps --all` to get the IDs, The `greeting.txt` file created by the first container did not exist in the
and then `docker rm -f <container-id>` to remove the containers. second container. That is because the writeable "top layer" of each container
is isolated. Even though both containers shared the same underlying layers that
make up the base image, the writable layer is unique to each container.
## Container volumes ## Container volumes