meteor-load-balancing

Example application demonstrating load balancing a meteor app using HAProxy

Setup

1. Install HAProxy

# on OSX with homebrew
brew install haproxy

2. Download this example

git clone https://github.com/alanning/meteor-load-balancing

Run

1. Open 5 terminal windows

2. From meteor-load-balancing directory:

# term1
haproxy -f haproxy.cfg

# term2
./run

# term3
./run 2

# term4
./run 3

# term5
./run 4

Open http://localhost:3000/ in some browsers.

Future work

• Include health checks as found here
• Use Smart Collections to avoid update delays
• Support auto-scaling, ex: haproxy-autoscale

Pull requests welcome.

Further Reading

• AWS Route53 health checks
• AWS HAProxy Layer via OpsCode
• HAProxy architecture examples
• Load Balancing your Meteor App
• SockJS HAProxy config

Configuring logging (syslog)

HAProxy logs to syslog so that there is no downtime required by utils such as logrotate. On OSX, syslog is not set up to listen to network log requests so a bit of configuration is needed before you will be able to see HAProxy log messages.

To configure syslog on OSX:

1. Backup syslogd start up file

sudo cp /System/Library/LaunchDaemons/com.apple.syslogd.plist /System/Library/LaunchDaemons/com.apple.syslogd.plist.backup

2. Convert binary file to xml to be human readable / editable

sudo plutil -convert xml1 /System/Library/LaunchDaemons/com.apple.syslogd.plist

3. Edit /System/Library/LaunchDaemons/com.apple.syslogd.plist and add the following snippet under the sockets node

 <key>NetworkListener</key>
 <dict>
   <key>SockServiceName</key>
   <string>syslog</string>
   <key>SockType</key>
   <string>dgram</string>
 </dict>

Should read like this now

 <key>Sockets</key>
 <dict>
    <key>AppleSystemLogger</key>
    <dict>
        <key>SockPathMode</key>
        <integer>438</integer>
        <key>SockPathName</key>
        <string>/var/run/asl_input</string>
    </dict>
    <key>BSDSystemLogger</key>
    <dict>
        <key>SockPathMode</key>
        <integer>438</integer>
        <key>SockPathName</key>
        <string>/var/run/syslog</string>
        <key>SockType</key>
        <string>dgram</string>
    </dict>
    <key>NetworkListener</key>
    <dict>
        <key>SockServiceName</key>
        <string>syslog</string>
        <key>SockType</key>
        <string>dgram</string>
    </dict>
 </dict>

4. Save the file

5. Convert back to binary file

sudo plutil -convert binary1 /System/Library/LaunchDaemons/com.apple.syslogd.plist

6. Restart syslogd

sudo launchctl unload /System/Library/LaunchDaemons/com.apple.syslogd.plist
sudo launchctl load /System/Library/LaunchDaemons/com.apple.syslogd.plist

7. Add the following entry to /etc/syslog.conf

local2.*  /var/log/haproxy.log

8. Include logging options in haproxy.cfg (already included in example haproxy.cfg)

    global
       log 127.0.0.1  local2 debug
    defaults
       mode http
       option httplog
       log global

9. Restart HAproxy

HAProxy output will now log to /var/log/haproxy.log

An easy way to view log output on OSX is to run Console.app