Updated docs to clarify that SSH config is not optional

SSH config is needed by Gerrit to define its sshd configuration.
In particular *IdentityFile* need to be specified for Gerrit
to know where to find the identity files.

Change-Id: I64b30f8880a54701c1769c80c20454e4c06d3570

1 files changed, 16 insertions, 2 deletions

diff --git a/src/main/resources/Documentation/config.md b/src/main/resources/Documentation/config.md
index 646d49c..2359599 100644
--- a/src/main/resources/Documentation/config.md
+++ b/src/main/resources/Documentation/config.md
@@ -13,6 +13,11 @@ with the command line:
   sudo su -c 'ssh mirror1.us.some.org echo' gerrit2
 ```
 
+*NOTE:* make sure the local user's ssh keys format is PEM, here how to generate them:
+```
+  ssh-keygen -m PEM -t rsa -C "your_email@example.com"
+```
+
 <a name="example_file">
 Next, create `$site_path/etc/replication.config` as a Git-style config
 file, for example to replicate in parallel to four different hosts:</a>
@@ -301,7 +306,7 @@ remote.NAME.createMissingRepositories
 	If the remote site was not available at the moment when a new
 	project was created, it will be created if during the replication
 	of a ref it is found to be missing.
-	
+
 	If false, repositories are never created automatically on this
 	remote.
 
@@ -401,7 +406,7 @@ remote.NAME.password
 File `~/.ssh/config`
 --------------------
 
-If present, Gerrit reads and caches `~/.ssh/config` at startup, and
+Gerrit reads and caches the `~/.ssh/config` at startup, and
 supports most SSH configuration options.  For example:
 
 ```
@@ -415,6 +420,15 @@ supports most SSH configuration options.  For example:
     PreferredAuthentications publickey
 ```
 
+*IdentityFile* and *PreferredAuthentications* must be defined for all the hosts.
+Here an example of the minimum `~/.ssh/config` needed:
+
+```
+  Host *
+    IdentityFile ~/.ssh/id_rsa
+    PreferredAuthentications publickey
+```
+
 Supported options:
 
   * Host