README.md

Varnish

Metadata associated with the Varnish collectd plugin can be found here. The relevant code for the plugin can be found here.

• Description
• Requirements and Dependencies
• Installation
• Configuration
• Usage
• Metrics
• License

DESCRIPTION

The Varnish collectd plugin collects metrics from Varnish and sends them to SignalFx.

Varnish Cache is a web application accelerator also known as a caching HTTP reverse proxy. You install it in front of any server that speaks HTTP and configure it to cache the contents. Varnish Cache is really, really fast. It typically speeds up delivery with a factor of 300 - 1000x, depending on your architecture.

FEATURES

Built-in dashboards

• Varnish (a): Overview of data from all Varnish servers.

  

• Varnish: Focus on a single Varnish server.

  

REQUIREMENTS AND DEPENDENCIES

Software	Version
collectd	5.1* or later (varnish 4.0+ requires collectd 5.5+)

INSTALLATION

1. On RHEL/CentOS and Amazon Linux systems, run the following command to install this plugin:

    yum install collectd-varnish
   

2. Download SignalFx's sample configuration file to /etc/collectd/managed_config.

3. Modify the sample configuration file to provide values that make sense for your environment, as described in Configuration below.

4. Restart collectd.

Special Instructions for installing Varnish 3 on Ubuntu

Starting with collectd 5.6.1-sfx0, the varnish plugin provided within the SignalFx Package only supports varnish 4. Follow these steps to add varnish 3 plugin support:

1. Copy the varnish3.so file to the collectd library directory /usr/lib/collectd/.

2. Update the configuration file 10-varnish.conf in your /etc/collectd/managed_config directory to show varnish3 instead of varnish as the name used by the LoadPlugin.

3. Restart collectd.

Example configuration for Varnish 3 on Ubuntu

LoadPlugin varnish3
<Plugin "varnish">
  <Instance>
    CollectCache       true
    CollectConnections true
    CollectBackend     true
    CollectSHM         true
    CollectESI         true
    CollectFetch       true
    CollectHCB         true
    CollectSMA         true
    CollectSMS         true
    CollectSM          true
    CollectTotals      true
    CollectWorkers     true
    CollectUptime      true
    CollectVCL         true
    CollectStruct      true
    CollectObjects     true
    CollectSession     true
    CollectVSM         true
  </Instance>
</Plugin>

CONFIGURATION

There is no configuration required for the varnish collectd plugin. The default configuration is setup to bring in data on a large variety of metrics.

If using the sample configuration file 10-varnish.conf, no additional configuration is required. The following optional settings allow you to configure the metrics that will be sent using this plugin:

Setting	Description	Default
CollectBackend	Back-end connection statistics, such as successful, reused, and closed connections.	enabled
CollectCache	Cache hits and misses.	enabled
CollectConnections	Number of client connections received, accepted and dropped.	enabled
CollectESI	Edge Side Includes (ESI) parse statistics.	enabled
CollectFetch	Statistics about fetches (HTTP requests sent to the backend).	enabled
CollectHCB	Inserts and look-ups in the crit bit tree based hash. Look-ups are divided into locked and unlocked look-ups.	enabled
CollectSHM	Statistics about the shared memory log, a memory region to store log messages which is flushed to disk when full.	enabled
CollectSM	file (memory mapped file) storage statistics.	enabled
CollectSMA	malloc or umem (umem_alloc(3MALLOC) based) storage statistics. The umem storage component is Solaris specific.	enabled
CollectSMS	synth (synthetic content) storage statistics. This storage component is used internally only.	enabled
CollectTotals	Collects overview counters, such as the number of sessions created, the number of requests and bytes transferred.	enabled
CollectWorkers	Collect statistics about worker threads.	enabled

USAGE

Sample of built-in dashboard in SignalFx:

METRICS

Field name	Description	Collected (Yes/No)	Collectd option
uptime	Child uptime	No	n/a
client_conn	Client connections accepted	Yes	CollectConnections
client_drop	Connection dropped, no sess	Yes
client_req	Client requests received	Yes
cache_hit	Cache hits	Yes	CollectCache
cache_hitpass	Cache hits for pass	Yes
cache_miss	Cache misses	Yes
backend_conn	Backend conn. success	Yes	CollectBackend
backend_unhealthy	Backend conn. not attempted	Yes
backend_busy	Backend conn. too many	Yes
backend_fail	Backend conn. failures	Yes
backend_reuse	Backend conn. reuses	Yes
backend_toolate	Backend conn. was closed	Yes
backend_recycle	Backend conn. recycles	Yes
backend_unused	Backend conn. unused	Yes
fetch_head	Fetch head	Yes	CollectFetch
fetch_length	Fetch with Length	Yes
fetch_chunked	Fetch chunked	Yes
fetch_eof	Fetch EOF	Yes
fetch_bad	Fetch had bad headers	Yes
fetch_close	Fetch wanted close	Yes
fetch_oldhttp	Fetch pre HTTP/1.1 closed	Yes
fetch_zero	Fetch zero len	Yes
fetch_failed	Fetch failed	Yes
n_sess_mem	N struct sess_mem	No	n/a
n_sess	N struct sess	No
n_object	N struct object	No
n_vampireobject	N unresurrected objects	No
n_objectcore	N struct objectcore	No
n_objecthead	N struct objecthead	No
n_smf	N struct smf	No
n_smf_frag	N small free smf	No
n_smf_large	N large free smf	No
n_vbe_conn	N struct vbe_conn	No
n_wrk	N worker threads	Yes	CollectWorkers
n_wrk_create	N worker threads created	Yes
n_wrk_failed	N worker threads not created	Yes
n_wrk_max	N worker threads limited	Yes
n_wrk_queue	N queued work requests	Yes
n_wrk_overflow	N overflowed work requests	Yes
n_wrk_drop	N dropped work requests	Yes
n_backend	N backends	No	n/a
n_expired	N expired objects	No
n_lru_nuked	N LRU nuked objects	No
n_lru_saved	N LRU saved objects	No
n_lru_moved	N LRU moved objects	No
n_deathrow	N objects on deathrow	No
losthdr	HTTP header overflows	No
n_objsendfile	Objects sent with sendfile	No
n_objwrite	Objects sent with write	No
n_objoverflow	Objects overflowing workspace	No
s_sess	Total Sessions	Yes	CollectTotals
s_req	Total Requests	Yes
s_pipe	Total pipe	Yes
s_pass	Total pass	Yes
s_fetch	Total fetch	Yes
s_hdrbytes	Total header bytes	Yes
s_bodybytes	Total body bytes	Yes
sess_closed	Session Closed	No	n/a
sess_pipeline	Session Pipeline	No
sess_readahead	Session Read Ahead	No
sess_linger	Session Linger	No
sess_herd	Session herd	No
shm_records	SHM records	Yes	CollectSHM
shm_writes	SHM writes	Yes
shm_flushes	SHM flushes due to overflow	Yes
shm_cont	SHM MTX contention	Yes
shm_cycles	SHM cycles through buffer	Yes
sm_nreq	allocator requests	Yes	CollectSM
sm_nobj	outstanding allocations	Yes
sm_balloc	bytes allocated	Yes
sm_bfree	bytes free	Yes
sma_nreq	SMA allocator requests	Yes	CollectSMA
sma_nobj	SMA outstanding allocations	Yes
sma_nbytes	SMA outstanding bytes	Yes
sma_balloc	SMA bytes allocated	Yes
sma_bfree	SMA bytes free	Yes
sms_nreq	SMS allocator requests	Yes	CollectSMS
sms_nobj	SMS outstanding allocations	Yes
sms_nbytes	SMS outstanding bytes	Yes
sms_balloc	SMS bytes allocated	Yes
sms_bfree	SMS bytes freed	Yes
backend_req	Backend requests made	No	n/a
n_vcl	N vcl total	No
n_vcl_avail	N vcl available	No
n_vcl_discard	N vcl discarded	No
n_purge	N total active purges	No
n_purge_add	N new purges added	No
n_purge_retire	N old purges deleted	No
n_purge_obj_test	N objects tested	No
n_purge_re_test	N regexps tested against	No
n_purge_dups	N duplicate purges removed	No
hcb_nolock	HCB Lookups without lock	Yes	CollectHCB
hcb_lock	HCB Lookups with lock	Yes
hcb_insert	HCB Inserts	Yes
esi_parse	Objects ESI parsed (unlock)	Yes	CollectESI
esi_errors	ESI parse errors (unlock)	Yes

LICENSE

This integration is released under the Apache 2.0 license. See LICENSE for more details.