swift-s3-cache-prewarmer
We have a few customers making extensive use of the S3 API in our Swift cluster.
To avoid putting too much load on Keystone, Swift can cache S3 credentials in a Memcache. However, when the customer
traffic is high enough to keep multiple parallel Swift API workers busy, once a cache entry expires, they all hit
Keystone simultaneously. To avoid this high request load on Keystone caused by expiring cache entries, this tool
periodically refreshes the cache entries so that they never expire.
Usage
Build with make/make install
or go get
or docker build
. Check out the --help
for how to run this.
Metrics
The prewarm
command exposes two gauges for each credential that was prewarmed:
swift_s3_cache_prewarm_last_run_secs
: UNIX timestamp in seconds of last successful cache prewarm (or 0 before the first successful prewarm)
swift_s3_cache_prewarm_duration_secs
: duration in seconds of last successful cache prewarm (or absent before the first successful prewarm)
Each time series has the labels userid
and accesskey
identifying the credential in question.