server: update readme

acs-server/readme.txt

+********************************************************************
+
 This is readme for Access control system server (ACS server/master).
 
+********************************************************************
 Its main job is to respond to authentication requests from RFID readers connected on CAN bus.
 
 The server is designed to be not accessible from ethernet network and be administred through ssh from outside
@@ -7,51 +10,63 @@ or from administrative application over secured channel.
 Redis server should be on the same machine or network as it is designed to be accesed only from trusted clients
 inside trusted environments.
 
+------------------
 Interactive usage:
+------------------
     1. Read prerequisites
-    2. Install python modules
+    2. Install python modules (pip module requred)
         python3 -m pip install -r requirements.txt --user
-    3. Use script start.sh (see parameters inside) or run src/acs-server.py --help for more info
+    3. Adjust parameters in start.sh
+    4. Run script start.sh or run src/acs-server.py --help for more info
 
-Install permanently as service (for systemd):
+---------------------------------------------
+Install permanently as service (for systemd init):
+---------------------------------------------
     1. Read prerequisites
-    2. Create system user for the service:
+    2. Create system user for the acs service:
         sudo useradd --system acs-srvc
         sudo mkdir /var/log/acs-server
         sudo chown acs-srvc:acs-srvc /var/log/acs-server
     3. Install python modules system wide
         sudo python3 -m pip install -r requirements.txt
-    2. Run build.sh (see parameters inside)
-    3. Use bundled acs-server.service (see parameters inside) and register as service:
+    4. Run build.sh (see parameters inside)
+    5. Use bundled acs-server.service (you may need to adjust settings inside)
         sudo cp acs-server.service /lib/systemd/system/acs-server.service
+    6. Enabble the service:
         sudo systemctl daemon-reload
         sudo systemctl enable acs-server
-    4. log files will be in /var/log/acs-server
+    7. Log file(s) will be in /var/log/acs-server
 
+--------------
 Prerequisites:
-    Linux (with SocketCAN)
-    CAN 2.0 controller supported by SocketCAN
-    Python 3.5 or higher (see below for module install)
-    Redis database (see below)
-        - It is the only implemented but others can be added.
+--------------
+    * Linux with SocketCAN (tested on 3.13.0)
+    * CAN 2.0 controller supported by SocketCAN
+    * Python 3.5 or higher + pip
+    * Redis database >= 2.0 (see below)
+        - It is the the only implemented but support for others can be added.
 
+----------------------------------------
 Example steps for meeting prerequisites:
+----------------------------------------
 
     CAN interface
-        * Connect CAN controller (USB-CAN, SPI-CAN, USB-UART-CAN, ...)
-        * You may need driver if not included in linux kernel
-        * You may need to add CAN controller to your device tree (only if using ARM platform with real CAN hardware)
-        * Enable auto setup of the CAN interface at startup -- add to /etc/network/interfaces:
+        1. You may need to install driver if not included in linux kernel
+        2. You may need to add CAN controller to your device tree (only if using ARM platform with real CAN hardware)
+        3. Add setup of the CAN interface at startup -- add to /etc/network/interfaces:
             auto can0
             iface can0 can static
                             bitrate 125000
-                            restart-ms 200
+                            restart-ms 1000
+                            txqueuelen 1000
+        4. Reboot
+        5. Connect CAN controller (USB-CAN, SPI-CAN, USB-UART-CAN, ...)
 
-    Redis database server setup example on port 6379 (steps for Debian distribution)
+    Redis server setup example on port 6379 (steps for Debian distribution)
         * Add "vm.overcommit_memory = 1" to /etc/sysctl.conf
-        * (optional) Disable transparent huge pages:
+        * [optional] Disable transparent huge pages (improves latency). Add to /etc/rc.local following line:
             echo never > /sys/kernel/mm/transparent_hugepage/enabled
-        * Build and install Redis (assumes /usr/local/bin in PATH)
+        * Compile and install Redis server (assumes /usr/local/bin in PATH)
             sudo apt-get install build-essential tcl
             wget http://download.redis.io/redis-stable.tar.gz
             tar xvzf redis-stable.tar.gz
@@ -60,13 +75,15 @@ Example steps for meeting prerequisites:
             sudo make install
         * Use configuration and init script bundled with this server
             sudo mkdir /etc/redis
-            sudo mkdir -r /var/redis/6379
+            sudo mkdir -p /var/redis/6379
             sudo cp ./redis_files/acs_redis_config.conf /etc/redis/redis_6379.conf
             sudo cp ./redis_files/asc_redis_init_script /etc/init.d/redis_6379
-        * (Optional) Modify maxmemory option in configuration file to suit your system
+        * [recommended] Modify maxmemory option in redis_6379.conf to suit your system
         * Enable Redis to run at startup
             sudo chmod +x /etc/init.d/redis_6379
             sudo update-rc.d redis_6379 defaults
+        * Allow connection to redis in firewall if on separate machine
+        * [recommended] Secure redis by adding password to /etc/redis/redis_6379.conf if accessible remotely
         * Reboot
-        * log files will be in /var/redis/6379
-        * allow connection to redis in firewall settings if on separate machine
+        * Redis database file will be in /var/redis/6379
+        * Redis log file will be in /var/log/redis_6379.log