Home • Explore • Blog • CI
☰



docker
2nd chunk of `content/manuals/desktop/troubleshoot-and-support/faqs/macfaqs.md`
c12fd5599aab882bbf4d7fbec579560cc30138fccdf9a88a00000001000009c7
- `Docker.raw`, space on the host is reclaimed within a few seconds.
- `Docker.qcow2`, space is freed by a background process after a few minutes.

Space is only freed when images are deleted. Space is not freed automatically when files are deleted inside running containers. To trigger a space reclamation at any point, run the command:

```console
$ docker run --privileged --pid=host docker/desktop-reclaim-space
```

Note that many tools report the maximum file size, not the actual file size.
To query the actual size of the file on the host from a terminal, run:

```console
$ cd ~/Library/Containers/com.docker.docker/Data/vms/0/data
$ ls -klsh Docker.raw
2333548 -rw-r--r--@ 1 username  staff    64G Dec 13 17:42 Docker.raw
```

In this example, the actual size of the disk is `2333548` KB, whereas the maximum size of the disk is `64` GB.

##### How do I reduce the maximum size of the file?

To reduce the maximum size of the disk image file:

1. Select **Settings** then  **Advanced** from the **Resources** tab.

2. The **Disk image size** section contains a slider that allows you to change the maximum size of the disk image. Adjust the slider to set a lower limit.

3. Select **Apply & Restart**.

When you reduce the maximum size, the current disk image file is deleted, and therefore, all containers and images are lost.

### How do I add TLS certificates?

You can add trusted Certificate Authorities (CAs) (used to verify registry
server certificates) and client certificates (used to authenticate to
registries) to your Docker daemon.

#### Add custom CA certificates (server side)

All trusted CAs (root or intermediate) are supported. Docker Desktop creates a
certificate bundle of all user-trusted CAs based on the Mac Keychain, and
appends it to Moby trusted certificates. So if an enterprise SSL certificate is
trusted by the user on the host, it is trusted by Docker Desktop.

To manually add a custom, self-signed certificate, start by adding the
certificate to the macOS keychain, which is picked up by Docker Desktop. Here is
an example:

```console
$ sudo security add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain ca.crt
```

Or, if you prefer to add the certificate to your own local keychain only (rather
than for all users), run this command instead:

```console
$ security add-trusted-cert -d -r trustRoot -k ~/Library/Keychains/login.keychain ca.crt
```

See also, [Directory structures for
certificates](#directory-structures-for-certificates).
Title: Managing Disk Image Size, TLS Certificates in Docker Desktop for Mac
Summary
This section describes how to reduce the maximum size of the Docker Desktop for Mac disk image. Note that reducing the maximum size deletes the existing image and all containers/images within it. The section also explains how to add TLS certificates for secure communication with Docker registries, including adding custom CA certificates to the macOS keychain for Docker Desktop to recognize them.