update configuration for rootless podman

I updated the configuration part of the tutorial on rootless podman. I added the
 order in which configuration files are read in and a hint, how users can create
 default configuration in the home directories.

Closes #6777

Signed-off-by: Niklas Netter <niknett@gmail.com>
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

2 files changed, 46 insertions, 5 deletions

diff --git a/docs/source/markdown/podman.1.md b/docs/source/markdown/podman.1.md
index 776ee7a67..74f02d147 100644
--- a/docs/source/markdown/podman.1.md
+++ b/docs/source/markdown/podman.1.md
@@ -217,7 +217,7 @@ the exit codes follow the `chroot` standard, see below:
 
 ## FILES
 
-**containers.conf** (`/usr/share/containers/containers.conf`)
+**containers.conf** (`/usr/share/containers/containers.conf`, `/etc/containers/containers.conf`, `$HOME/.config/containers/containers.conf`)
 
     Podman has builtin defaults for command line options. These defaults can be overridden using the containers.conf configuration files.
 
@@ -235,13 +235,13 @@ When Podman runs in rootless mode, the file `$HOME/.config/containers/mounts.con
 
     Signature verification policy files are used to specify policy, e.g. trusted keys, applicable when deciding whether to accept an image, or individual signatures of that image, as valid.
 
-**registries.conf** (`/etc/containers/registries.conf`)
+**registries.conf** (`/etc/containers/registries.conf`, `$HOME/.config/containers/registries.conf`)
 
     registries.conf is the configuration file which specifies which container registries should be consulted when completing image names which do not include a registry or domain portion.
 
     Non root users of Podman can create the `$HOME/.config/containers/registries.conf` file to be used instead of the system defaults.
 
-**storage.conf** (`/etc/containers/storage.conf`)
+**storage.conf** (`/etc/containers/storage.conf`, `$HOME/.config/contaners/storage.conf`)
 
     storage.conf is the storage configuration file for all tools using containers/storage
 
diff --git a/docs/tutorials/rootless_tutorial.md b/docs/tutorials/rootless_tutorial.md
index 821c07647..ba28655f6 100644
--- a/docs/tutorials/rootless_tutorial.md
+++ b/docs/tutorials/rootless_tutorial.md
@@ -106,9 +106,50 @@ Once the Administrator has completed the setup on the machine and then the confi
 
 ### User Configuration Files
 
-The Podman configuration files for root reside in `/usr/share/containers` with overrides in `/etc/containers`.  In the rootless environment they reside in `${XDG_CONFIG_HOME}/containers` (usually `~/.config/containers`) and are owned by each individual user.  The main files are `containers.conf` and `storage.conf` and the user can modify these files as they wish.
+The Podman configuration files for root reside in `/usr/share/containers` with overrides in `/etc/containers`.  In the rootless environment they reside in `${XDG_CONFIG_HOME}/containers` (usually `~/.config/containers`) and are owned by each individual user.
 
-The default authorization file used by the `podman login` and `podman logout` commands reside in `${XDG_RUNTIME_DIR}/containers/auth.json`.
+The three main configuration files are [containers.conf](https://github.com/containers/common/blob/master/docs/containers.conf.5.md), [storage.conf](https://github.com/containers/storage/blob/master/docs/containers-storage.conf.5.md) and [registries.conf](https://github.com/containers/image/blob/master/docs/containers-registries.conf.5.md). The user can modify these files as they wish.
+
+#### containers.conf
+Podman reads
+1. `/usr/share/containers/containers.conf`
+2. `/etc/containers/containers.conf`
+3. `$HOME/.config/containers/containers.conf`
+
+if they exist in that order. Each file can override the previous for particular fields.
+
+#### storage.conf
+For `storage.conf` the order is
+1. `/etc/containers/storage.conf`
+2. `$HOME/.config/containers/storage.conf`
+
+In rootless podman certain fields in `/etc/containers/storage.conf` are ignored. These fields are:
+```
+graphroot=""
+ container storage graph dir (default: "/var/lib/containers/storage")
+ Default directory to store all writable content created by container storage programs.
+
+runroot=""
+ container storage run dir (default: "/var/run/containers/storage")
+ Default directory to store all temporary writable content created by container storage programs.
+```
+In rootless podman these fields default to
+```
+graphroot="$HOME/.local/share/containers/storage"
+runroot="$XDG_RUNTIME_DIR/containers"
+```
+[$XDG_RUNTIME_DIR](https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html#variables) defaults on most systems to `/run/user/$UID`.
+
+#### registries
+Registry configuration is read in by this order
+1. `/etc/containers/registries.conf`
+2. `/etc/containers/registries.d/*`
+3. `HOME/.config/containers/registries.conf`
+
+The files in the home directory should be used to configure rootless podman for personal needs. These files are not created by default. Users can copy the files from `/usr/share/containers` or `/etc/containers` and modify them.
+
+#### Authorization files
+ The default authorization file used by the `podman login` and `podman logout` commands reside in `${XDG_RUNTIME_DIR}/containers/auth.json`.
 
 ### Using volumes