Building a more perfect Syslog Collection Infrastructure

A little while back I created a bit of code to help get data from linux systems in real time where the Splunk Universal Forwarder could not be installed. At the time we had a few limitations the biggest problem being time stamps were never parsed only “current” time on the indexer could be used.  Want to try out version 2 lets get started! First let me explain what we are doing

If you manage a Splunk environment with high rate sources such as a Palo Alto firewall or Web Proxy you will notice that events are not evenly distributed over the indexers because the the data is not evenly balanced across your aggregation tier. The reasons for this are boiled down to “time based load balancing” in Larger environments the universal forwarder may not be able to split by time to distribute a high load. So what is an admin to do? Lets look for a connection load balancing solution. We need to find a way to switch from “SYSLOG” to HTTP(s) so we can utilize a proper load balancer. How will we do this?

  1. Using containers we will dedicate one or more instance of RSYSLOG for each “type” of data,
  2. Use a custom plugin to package and forward batches of events over http(s)
  3. Use a load balancer configured for least connected round robin to balance the batches of events

What you need

  • At least two indexers with http event collector, more = better. The “benefits” of this solution require collection on the indexer dedicated collectors will not be a adequate substitute
  • One load balancer, I use HA Proxy
  • One syslog collection server with rsyslog 8.24+ host I use LXC instances hosted on proxmox. Optimal deployment will utilize 1 collector per source technology. For example 1 instance collecting for Cisco IOS and another for Palo Alto Firewalls. Using advanced configuration and filters you can combine several low volume source.
  • A GUID if you need one generated there are many ways this one is quick and easy https://www.guidgenerator.com/online-guid-generator.aspx

Basic Setup

  1. Follow docs, to setup HTTP event collector on your indexers, note if your indexers are clustered docs does not cover this, you must create the configuration manually be sure to generate a unique GUID manually. Clusters environments can use the sample configuration below:
  2. Follow documentation for your load balancer of choice to create a http VIP with https back end servers. HEC listens on 8088 by default
  3. Grab the code and configuration examples from bitbucket
    1. Deploy the script omsplunkhec.py to /opt/rsyslog/ ensure the script is executable
    2. Review rsyslogd.d.conf.example and your configuration in /etc/rsyslog.d/00-splunkhec.conf replace the GUID and IP with your correct values
    3. Restart rsyslog

What to expect, My hope data balance Zen.

HTTP Event Collector inputs.conf example deployed via master-apps

[http] 
disabled=0
port=8088
#
[http://SM_rsyslog_routerboard]
disabled=0
index=main
token=DAA61EE1-F8B2-4DB1-9159-6D7AA5220B21
indexes=main,summary

Example /etc/rsyslog.d/00-splunk.conf

This example will listen on 514 TCP and UDP sending events via http, be sure to replace the GUID and ip address

module(load="imudp")
input(type="imudp" port="514" ruleset="default_file")
module(load="imptcp")
input(type="imptcp" port="514" ruleset="default_file")
module(load="omprog")

ruleset(name="default_file"){
    $RulesetCreateMainQueue    
    action(type="omprog"
       binary="/opt/rsyslog/omsplunkhec.py DAA61EE1-F8B2-4DB1-9159-6D7AA5220B21 192.168.100.70 --sourcetype=syslog --index=main" 
       template="RSYSLOG_TraditionalFileFormat")
    stop
}

Example HAProxy Configuration 1.7 /etc/haproxy/haproxy.cfg

 

global
        log /dev/log    local0
        log /dev/log    local1 notice
        chroot /var/lib/haproxy
        stats socket /run/haproxy/admin.sock mode 660 level admin
        stats timeout 30s
        user haproxy
        group haproxy
        daemon
        # Default SSL material locations
        ca-base /etc/ssl/certs
        crt-base /etc/ssl/private
        # Default ciphers to use on SSL-enabled listening sockets.
        # For more information, see ciphers(1SSL).
        ssl-default-bind-ciphers kEECDH+aRSA+AES:kRSA+AES:+AES256:RC4-SHA:!kEDH:!LOW:!EXP:!MD5:!aNULL:!eNULL
defaults
        log     global
        mode    http
        option  httplog
        option  dontlognull
        timeout connect 5000
        timeout client  50000
        timeout server  50000
        errorfile 400 /etc/haproxy/errors/400.http
        errorfile 403 /etc/haproxy/errors/403.http
        errorfile 408 /etc/haproxy/errors/408.http
        errorfile 500 /etc/haproxy/errors/500.http
        errorfile 502 /etc/haproxy/errors/502.http
        errorfile 503 /etc/haproxy/errors/503.http
        errorfile 504 /etc/haproxy/errors/504.http
listen  stats   
        bind            *:1936
        mode            http
        log             global
        maxconn 10
        clitimeout      100s
        srvtimeout      100s
        contimeout      100s
        timeout queue   100s
        stats enable
        stats hide-version
        stats refresh 30s
        stats show-node
        stats auth admin:password
        stats uri  /haproxy?stats
frontend localnodes
    bind *:8088
    mode http
    default_backend nodes
backend nodes
    mode http
    balance leastconn
    option forwardfor
    http-request set-header X-Forwarded-Port %[dst_port]
    http-request add-header X-Forwarded-Proto https if { ssl_fc }
    option httpchk
    server idx2 192.168.100.52:8088 ssl verify none check 
    server idx1 192.168.100.51:8088 ssl verify none check 

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