docs: add kata-runtime to Docker daemon.json

Fixes: #484

Signed-off-by: Stefan Heitmüller <morphsen@gmx.com>

install/docker/centos-docker-install.md

@@ -24,7 +24,9 @@
    For more information on installing Docker please refer to the
    [Docker Guide](https://docs.docker.com/engine/installation/linux/centos).
 
-2. Configure Docker to use Kata Containers by default with the following commands:
+2. Configure Docker to use Kata Containers by default with one of the following methods:
+
+    1. systemd
 
         ```bash
         $ sudo mkdir -p /etc/systemd/system/docker.service.d/
@@ -35,6 +37,21 @@
         EOF
         ```
 
+    2. Docker `daemon.json`
+
+        Add the following definitions to `/etc/docker/daemon.json`:
+
+        ```json
+        {
+          "default-runtime": "kata-runtime",
+          "runtimes": {
+            "kata-runtime": {
+              "path": "/usr/bin/kata-runtime"
+            }
+          }
+        }
+        ```
+
 3. Restart the Docker systemd service with the following commands:
 
     ```bash
@@ -51,4 +68,4 @@
     ```
 
     The previous command shows details of the kernel version running inside the
-   container, which is different to the host kernel version.
+    container, which is different from the host kernel version.

install/docker/fedora-docker-install.md

@@ -25,7 +25,9 @@
    For more information on installing Docker please refer to the
    [Docker Guide](https://docs.docker.com/engine/installation/linux/fedora).
 
-2. Configure Docker to use Kata Containers by default with the following commands:
+2. Configure Docker to use Kata Containers by default with one of the following methods:
+
+    1. systemd
 
         ```bash
         $ sudo mkdir -p /etc/systemd/system/docker.service.d/
@@ -36,6 +38,21 @@
         EOF
         ```
 
+    2. Docker `daemon.json`
+
+        Add the following definitions to `/etc/docker/daemon.json`:
+
+        ```json
+        {
+          "default-runtime": "kata-runtime",
+          "runtimes": {
+            "kata-runtime": {
+              "path": "/usr/bin/kata-runtime"
+            }
+          }
+        }
+        ```
+
 3. Restart the Docker systemd service with the following commands:
 
    ```bash

install/docker/rhel-docker-install.md

@@ -25,7 +25,9 @@
    For more information on installing Docker please refer to the
    [Docker Guide](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux_atomic_host/7/html-single/getting_started_with_containers/#getting_docker_in_rhel_7).
 
-2. Configure Docker to use Kata Containers by default with the following commands:
+2. Configure Docker to use Kata Containers by default with one of the following methods:
+
+    1. systemd
 
         ```bash
         $ sudo mkdir -p /etc/systemd/system/docker.service.d/
@@ -36,6 +38,21 @@
         EOF
         ```
 
+    2. Docker `daemon.json`
+
+        Add the following definitions to `/etc/docker/daemon.json`:
+
+        ```json
+        {
+          "default-runtime": "kata-runtime",
+          "runtimes": {
+            "kata-runtime": {
+              "path": "/usr/bin/kata-runtime"
+            }
+          }
+        }
+        ```
+
 3. Restart the Docker systemd service with the following commands:
 
    ```bash

install/docker/ubuntu-docker-install.md

@@ -28,7 +28,9 @@
    For more information on installing Docker please refer to the
    [Docker Guide](https://docs.docker.com/engine/installation/linux/ubuntu).
 
-2. Configure Docker to use Kata Containers by default with the following commands:
+2. Configure Docker to use Kata Containers by default with one of the following methods:
+
+    1. systemd
 
         ```bash
         $ sudo mkdir -p /etc/systemd/system/docker.service.d/
@@ -39,6 +41,21 @@
         EOF
         ```
 
+    2. Docker `daemon.json`
+
+        Add the following definitions to `/etc/docker/daemon.json`:
+
+        ```json
+        {
+          "default-runtime": "kata-runtime",
+          "runtimes": {
+            "kata-runtime": {
+              "path": "/usr/bin/kata-runtime"
+            }
+          }
+        }
+        ```
+
 3. Restart the Docker systemd service with the following commands:
 
    ```bash