README
¶
cache
cache enables a frontend cache.
Syntax
cache [TTL] [ZONES...]
- TTL max TTL in seconds. If not specified, the maximum TTL will be used which is 1 hour for noerror responses and half an hour for denial of existence ones.
- ZONES zones it should cache for. If empty, the zones from the configuration block are used.
Each element in the cache is cached according to its TTL (with TTL as the max). For the negative cache, the SOA's MinTTL value is used. A cache can contain up to 10,000 items by default.
If you want more control:
cache [TTL] [ZONES...] {
success CAPACITY [TTL]
denial CAPACITY [TTL]
}
- TTL and ZONES as above.
success, override the settings for caching succesful responses, CAPACITY indicates the maximum number of packets we cache before we start evicting (LRU). TTL overrides the cache maximum TTL.denial, override the settings for caching denial of existence responses, CAPACITY indicates the maximum number of packets we cache before we start evicting (LRU). TTL overrides the cache maximum TTL.
There is a third category (error) but those responses are never cached.
The minimum TTL allowed on resource records is 5 seconds.
If monitoring is enabled (via the prometheus directive) then the following extra metrics are added:
- coredns_cache_hit_count_total, and
- coredns_cache_miss_count_total
They both work on a per-zone basis and just count the hit and miss counts for each query.
Examples
cache 10
Enable caching for all zones, but cap everything to a TTL of 10 seconds.
proxy . 8.8.8.8:53
cache example.org
Proxy to Google Public DNS and only cache responses for example.org (or below).
Documentation
¶
Overview ¶
Package cache implements a cache.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Cache ¶
type Cache struct {
Next middleware.Handler
Zones []string
// contains filtered or unexported fields
}
Cache is middleware that looks up responses in a cache and caches replies. It has a success and a denial of existence cache.
type ResponseWriter ¶
type ResponseWriter struct {
dns.ResponseWriter
*Cache
}
ResponseWriter is a response writer that caches the reply message.
Source Files