Skip to main content

Pushing Logs from Software - Apache

Stephanie R.
Updated

This guide will present you with three non-intrusive ways to send logs to the Logs Data platform:

  • ask Apache to pipe log entries directly to the platform.
  • use syslog-ng to parse and send all of your logs
  • setup filebeat with the Apache module

Apache access logs are very valuable. They show the activity of your visitors, page delivery time, code results, user agents that accessed your websites, etc. Logs Data Platform helps you to fully analyze this key information.

The default Apache log line looks like this:

51.255.160.250 - - [23/Jan/2016:19:33:03 +0100] "GET / HTTP/1.1" 200 14211 "-" "Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.12) Gecko/20050915 Firefox/1.0.7"

This line already gives a lot of information but it can be difficult to extract really useful data from plain text logs. There are many ways to export your Apache logs: logstash, beats, graylog-collector, syslog-ng, rsyslog, gelf, or apache module.

 

Requirements

 

Instructions

Use Apache to send logs directly

NOTE: The following procedure has the advantage of a quick setup but is NOT recommended at all in production as it can block the Apache process in the case of heavy traffic. In production, please use a non-blocking solution like the second solution in this guide, or this one: Pushing Logs with a Forwarder - Filebeat (Linux).

 

Global Apache configuration

First, we will configure Apache2 to send all Virtual Hosts logs to one stream.

NOTE: If you have any log related configuration in your virtual hosts, you must remove them or head to the next section to add a specific virtual host configuration.

We use the CustomLog format directive to transform Apache logs in LTSV format and ship them to the Logs Data Platform with the proper OVHcloud token. Note that three fields are mandatory with the LTSV format; host, message, and time (in the RFC 3339 format). Refer to the examples below to learn how to fill in these fields. Please create the file /etc/httpd/conf-enabled/ldp.conf or /etc/apache2/conf-enabled/ldp.conf (it depends on your distribution) and insert the following:

 LogFormat "X-OVH-TOKEN:XXXXXXXXXXX\tdomain:%V\thost:%h\tserver:%A\ttime:%{sec}t\tident:%l\tuser:%u\tmethod:%m\tpath:%U%q\tprotocol:%H\tstatus_int:%>s\tsize_int:%b\treferer:%{Referer}i\tagent:%{User-Agent}i\tresponse_time_int:%D\tcookie:%{cookie}i\tset_cookie:%{Set-Cookie}o\tmessage:%h %l %u %t \"%r\" %>s %b\n" combined_ltsv
 CustomLog "|/usr/bin/openssl s_client -connect <your_cluster>.logs.ovh.com:12201" combined_ltsv
 ErrorLog syslog:local1

If you want to send your logs to an additional stream, you would need to repeat this snippet and change the LogFormat name combined_ltsv of your new snippet to a new name.

Note that you will have to replace the address and the port of <your_cluster>.logs.ovh.com with the one you have been assigned to (check the Home page to retrieve it). Ensure that the full path of openssl is correct for your system or it won't work. Also ensure that your X-OVH-TOKEN is properly written. This tutorial only covers how to send your access logs to the Logs Data platform. To send your Error logs, you should configure your syslog template to send logs to Logs Data platform. Finally, check that you don't use any CustomLog option in your VirtualHost configuration since the VirtualHost configuration has precedence over global configuration.

You also need to modify the /etc/httpd/sites-enabled/000-default.conf  or /etc/apache2/sites-enabled/000-default.conf file to ensure that the ErrorLog and CustomLog lines (shown below in yellow) are commented out:

<VirtualHost *:80>
# The ServerName directive sets the request scheme, hostname and port that
# the server uses to identify itself. This is used when creating
# redirection URLs. In the context of virtual hosts, the ServerName
# specifies what hostname must appear in the request's Host: header to
# match this virtual host. For the default virtual host (this file) this
# value is not decisive as it is used as a last resort host regardless.
# However, you must set it for any further virtual host explicitly.
#ServerName www.example.com

ServerAdmin webmaster@localhost
DocumentRoot /var/www/html

# Available loglevels: trace8, ..., trace1, debug, info, notice, warn,
# error, crit, alert, emerg.
# It is also possible to configure the loglevel for particular
# modules, e.g.
#LogLevel info ssl:warn

#ErrorLog ${APACHE_LOG_DIR}/error.log
#CustomLog ${APACHE_LOG_DIR}/access.log combined

# For most configuration files from conf-available/, which are
# enabled or disabled at a global level, it is possible to
# include a line for only one particular virtual host. For example the
# following line enables the CGI configuration for this host only
# after it has been globally disabled with "a2disconf".
#Include conf-available/serve-cgi-bin.conf
</VirtualHost>

 

VirtualHost configuration

If you want to only send logs from a specific VirtualHost, or send specific information about one VirtualHost, use this configuration to send logs to Logs Data platform:

<VirtualHost *:80>
   ServerName www.example.com
   ServerAlias example.com
   DocumentRoot /var/www/www.example.com

   LogLevel warn
   ErrorLog /var/log/httpd/www.example.com_error.log
   CustomLog /var/log/httpd/www.example.com_access.log combined
   CustomLog "|/usr/bin/openssl s_client -connect <your_cluster>.logs.ovh.com:12201" "X-OVH-TOKEN:XXXXXXXXXXXXXX\tdomain:%V\thost:%h\tserver:%A\tident:%l\tuser:%u\ttime:%{sec}t\tmethod:%m\tpath:%U%q\tprotocol:%H\tstatus_int:%>s\tsize_int:%b\treferer:%{Referer}i\tagent:%{User-Agent}i\tresponse_time_int:%D\tcookie:%{cookie}i\tset_cookie:%{Set-Cookie}o\tmessage:%h %l %u %t \"%r\" %>s %b\n"
   ErrorLog syslog:local1
</VirtualHost>

This is what you see on Graylog when you send your logs. The logs are already nicely parsed and you can immediately launch specific searches on them:

operate_LDP_ingest_apache01*.png

 

Using a syslog-ng template

If you already have syslog-ng on your host and you want to leverage its features (log rotation, automatic reconnection, multiple destinations). Here are the configuration snippets allowing you to use this software.

Apache configuration

The configuration is pretty similar to the one used in the first part of this document. The only change is the path of the log file.

 LogFormat "X-OVH-TOKEN:XXXXXXXXXXX\tdomain:%V\thost:%h\tserver:%A\ttime:%{sec}t\tident:%l\tuser:%u\tmethod:%m\tpath:%U%q\tprotocol:%H\tstatus_int:%>s\tsize_int:%b\treferer:%{Referer}i\tagent:%{User-Agent}i\tresponse_time_int:%D\tcookie:%{cookie}i\tset_cookie:%{Set-Cookie}o\tmessage:%h %l %u %t \"%r\" %>s %b\n" combined_ltsv
 CustomLog /var/log/httpd/access.log combined_ltsv
 ErrorLog syslog:local1

 

Syslog-ng configuration

To keep things brief, this extract has only the parts relevant to the access log file. The syslog-ng tutorial covers the configuration for any syslog file (like the error log file). This configuration is only valid for syslog-ng 3.8+.

 source s_apache {
     file("/var/log/httpd/access.log" flags(no-parse));
 };

 template t_apache_access_log {
     template("type:apache-access.log\tX-OVH-TOKEN:XXXXXXXXXXXXXXXX\ttime:${APACHE.TIMESTAMP}\thost:${HOST}\tremote_ip:${APACHE.CLIENT_IP}\trequest:${APACHE.REQUEST_URL}\tstatus_code:${APACHE.REQUEST_STATUS}\treponse_size:${APACHE.CONTENT_LENGTH}\treferer:${APACHE.REFERER}\tuser_agent:${APACHE.USER_AGENT}\tmessage:${MSG}\n");
     template_escape(no);
 };

 destination dt_apache_access_ldp {
     tcp("XXX.logs.ovh.com"
         port(12201)
         tls(ca_dir("/etc/ssl/certs"))
         ts_format("rfc3339") template(t_apache_access_log)
         keep-alive(yes)
         so_keepalive(yes)
         log-fifo-size(30000)
     );
 };

 parser p_apache {
     csv-parser(columns("APACHE.CLIENT_IP", "APACHE.IDENT_NAME", "APACHE.USER_NAME",
 "APACHE.TIMESTAMP", "APACHE.REQUEST_URL", "APACHE.REQUEST_STATUS",
 "APACHE.CONTENT_LENGTH", "APACHE.REFERER", "APACHE.USER_AGENT")
     flags(escape-double-char,strip-whitespace)
     delimiters(" ")
     quote-pairs('""[]')
     );
 };

 log {
     source(s_apache);
     parser(p_apache);
     destination(dt_apache_access_ldp);
 };

 

Apache logs format

If you want to use your own log format and include some useful information here is a cheat sheet for you (note that the labels follow the field naming conventions).

The full list of logs formats that can be used in Apache is described here mod_log_config.html.

Recommended Label About Format String of Apache mod_log_config Format String of nginx log format
time Time the request was received %t $time_local
host Remote host %h $remote_addr
forwardedfor X-Forwarded-For header %{X-Forwarded-For}i $http_x_forwarded_for
ident Remote logname %l  
user Remote user %u $remote_user
req First line of request %r $request
method Request method %m $request_method
uri Request URI %U%q $request_uri
protocol Requested Protocol (usually "HTTP/1.0" or "HTTP/1.1") %H $server_protocol
status Status code %>s $status
size_int Size of response in bytes, excluding HTTP headers. %B (or '%b' for compatibility with combined format) $body_bytes_sent
reqsize_int Bytes received, including request and headers. %I (mod_log_io required) $request_length
referer Referer header %{Referer}i $http_referer
ua User-Agent header %{User-agent}i $http_user_agent
vhost Host header %{Host}i $host
reqtime_microsec_int The time taken to serve the request, in microseconds %D  
reqtime_int The time taken to serve the request, in seconds %T $request_time
cache X-Cache header %{X-Cache}o $upstream_http_x_cache
runtime_num Execution time for processing some request, e.g. X-Runtime header for application server or processing time of SQL for DB server. %{X-Runtime}o $upstream_http_x_runtime
apptime_num Response time from the upstream server - $upstream_response_time

 

Using Filebeat

The latest releases of Filebeat have a dedicated module for Apache2. This solution is ready-to-use to configure and is more production-ready. The complete procedure of its installation is described on this page in the Apache logs use case.

 

Go further

For more information and tutorials, please see our other Logs Data Platform support guides or explore the guides for other OVHcloud products and services.

Related articles