python readme update: varnish cache

diff --git a/python.d/README.md b/python.d/README.md
index 00f81342e3c05f2a80e3342ae3c9e3789d4302d8..c3209f2dc6cbd7f0af98c2e20ceb1682997b2b05 100644 (file)
--- a/python.d/README.md
+++ b/python.d/README.md
@@ -1024,3 +1024,69 @@ Without configuration, module attempts to connect to `http://localhost:8080/mana
 So it will probably fail.
 
 --- 
+
+# varnish cache
+
+Module uses the `varnishstat` command to provide varnish cache statistics.
+
+It produces:
+
+1. **Client metrics**
+ * session accepted
+ * session dropped
+ * good client requests received
+
+2. **All history hit rate ratio**
+ * cache hits in percent
+ * cache miss in percent
+ * cache hits for pass percent
+
+3. **Curent poll hit rate ratio**
+ * cache hits in percent
+ * cache miss in percent
+ * cache hits for pass percent
+
+4. **Thread-related metrics** (only for varnish version 4+)
+ * total number of threads
+ * threads created
+ * threads creation failed
+ * threads hit max
+ * length os session queue
+ * sessions queued for thread
+
+5. **Backend health**
+ * backend conn. success
+ * backend conn. not attempted
+ * backend conn. too many
+ * backend conn. failures
+ * backend conn. reuses
+ * backend conn. recycles
+ * backend conn. retry
+ * backend requests made
+
+6. **Memory usage**
+ * memory available in megabytes
+ * memory allocated in megabytes
+
+7. **Problems summary**
+ * session dropped
+ * session accept failures
+ * session pipe overflow
+ * backend conn. not attempted
+ * fetch failed (all causes)
+ * backend conn. too many
+ * threads hit max
+ * threads destroyed
+ * length of session queue
+ * HTTP header overflows
+ * ESI parse errors
+ * ESI parse warnings
+
+8. **Uptime**
+ * varnish instance uptime in seconds
+
+### configuration
+
+No configuration is needed.
+
+---