Varnish : an introduction
Kacper Wysocki
Infrastructure Consultant
High Performance Scaling Expert
Security Specialist
Kick-ass snowboarder
problems solved
Some problems are easy to solve
with varnish.
throughput
peak periods and scalability
latency
minimal round-trip latency
availability
protects frontend from
maintenance windows and
outages.
DDoS attacks
varnish takes the load,
without breaking a sweat
dampening attack on appservers
mobile detection
detect-and-redirect or simply serve a different site
realtime monitoring
realtime http-level control and transparency
unified brand impression
simplify multi-domain site routing,
rewrites and redirects
How does Varnish do it?
modern code
(for modern architectures)
written for 64-bit OS
demand-driven design
features solve
real-world problems
only
super-threaded
shared-nothing work delegation
can handle
100K requests
** per second**
fast critical path
request must be delivered
with minimal effort
real-time insights
shared memory log and
for metering,
monitoring
and troubleshooting
extensible configuration
Varnish Configuration Language
powerful yet simple
Typical Deployment Scenarios
Varnish as a loadbalancer
Varnish behind the loadbalancer
Varnish on the appserver
Redundancy
Deploy 2 or more Varnish servers
for high availability
Deployment Requirements
- When you deploy Varnish,
-
what do you need to do?
Typical time to deploy:
3 working days
Decisions:
-
Subscription level
-
Frontend
recommended scenario #1: varnish as load balancer
Responsibilites
We need these things before deployment:
-
system overview
-
frontend domain names
-
backend hostnames, ip, port numbers
-
DNS / load balancer config
-
host(s) to deploy Varnish on
Typical Deployment
what to do, when, how. next step?
Day 1
installation and configuration
Varnish installed on hosts.
Initial VCL set up.
Day 2:
preprod Quality Assurance.
Production Deployment
Day 3:
post-prod QA
VAC install
Day 4 (offsite):
Cache tuning
spillover from day 3
Subscriptions
Varnish Administration Console
Support
Access to highly qualified Varnish consultants.
Device detection
What mobile device is connected?
Paywall
check whether reader has access to page he is requesting
before Varnish delivers it.
Training
for developers and system administrators
Custom Statistics Daemon
Real-time aggregated stats from varnish cluster
Custom Stats
Here are some examples of the type of statistics you may track:
The URLs that take the longest time to load
URLs that get most hits
URLs that get the most 50x response code errors
Cache hits and cache misses
Products that are attracting the most traffic
Where traffic is coming from
Clients that are generating load on various parts of the system and where are they located.
Things to bring home
how simple it is to get going
very simple
your life will be easier
and you will sleep better at night
Thank you
We take questions
at the end plz