This document discusses Varnish Extend, which provides tools and services to flexibly deploy Varnish caching and other content delivery technologies. It can be used to build hybrid CDNs, leverage existing data centers for delivery, or create a fully custom DIY CDN. The key components are Varnish Plus for caching, Cedexis Radar for intelligent routing, and Cedexis Purge for unified purging across delivery architectures. An example implementation is shown with Varnish deployed at edge POPs and an origin server, using Varnish High Availability (VHA) for replication between nodes. Configuration details are provided for VCS statistics, Cedexis Radar and Openmix load balancing, and VHA. The document demonstrates how V

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2. Ultimate Goal and Problem
Network LatencyThroughput
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3. Varnish Extend - What is it?
Bundled Software and Services
Aimed to provide
● Flexible deployment methodology for Varnish and other delivery mechanisms
● A set of tools that enables easy “hybridisation” of technologies
Example use cases:
- Hybrid CDN/Varnish
- Leverage existing data centres for content delivery
- Full DIY CDN
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4. Three Key Components
Varnish Plus (caching)
● Fine-grained cache control important for good off-loads
● High availability
● Custom Statistics - Visibility of near real-time reporting
Cedexis Radar/Openmix (RUM based Intelligent Routing and GSLB)
● Move beyond Geo to End-User Feedback
● “Programmable” load-balancing to enable flexibility and fine-grained control
Cedexis Purge (Unified Purging)
● Purge Page and object Content Across delivery architectures.
● Purge Method Supported (No Bans) 4

5. Varnish Extend
Extending your Content Delivery Capabilities and Control
Private CDN /
Edge node(s)
End UsersAccess
Network
CDN
Operators
Content Origin Global Traffic
Management
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6. ● Overall depicted edge capacity
is 80Gbps (8 x 10Gbps).
● DNS based edge routing allows
clients to pin to an edge node,
making prefetch effective.
● Both tiers can scale horizontally
by adding more nodes,
increasing overall storage and
capacity.
● Live video content is malloc
only.
● Edge and storage tiers can live
in the same rack.
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7. Varnish Custom Statistics (VCS)
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8. Cedexis
Radar Real-user Monitoring (RUM)
- Tag Based.
- Community Testing of CDN’s and Clouds
- Monitoring of Data Centres
Openmix Load-Balancing
- Programmable “Business logic” Load-Balancing
- JS based / Forms based configuration
- ECMA5 (Some 6)
- DNS Decisions
- CNAME / A/AAAA Record Responses
- TTL
- HTTP API
- “Decisions” in a restful response
- Multi-Decision responses (ordered lists)
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9. Prerequisites
● Basic experience with command line in Linux/Unix systems
● Basic understanding of Varnish Configuration Language (VCL)
● Varnish Extend subscription
● Root access to virtual or real hosts. In this demo:
○ Origin server
○ POPs
● Access to your DNS Architecture 9

10. Design
Image:
https://media.licdn.com/
mpr/mpr/shrinknp_800_8
00/p/5/005/0b0/060/2590
45e.jpg
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11. Edge 3
Location: Asia
Edge 2
Location: Europe
Varnish Plus
Edge 1
Location: U.S.
Varnish Plus
Location: NYC
Origin Server
Varnish Plus
Tier 2: POPsTier 1: Shield
Varnish PlusVarnish Plus
VHA
Demo
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12. Implementation 12

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14. TLS configuration
● Repository configuration for
○ varnish-plus-addon-ssl
● Certificate:
○ From valid certification authority
○ Let’s Encrypt
○ make-dummy-cert
● VCL to connect from POPs to origin server:
backend default {
.host = "origin-frankfurt.varnish-software.com";
.port = "https";
.ssl = 1;
.ssl_nosni = 1;
.ssl_noverify = 1;
}
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15. Hitch configuration
/etc/hitch/hitch.conf
frontend = "[*]:443"
backend = "[127.0.0.1]:6086"
pem-file = "/etc/ssl/bundles/varnish-software.com.bundle"
write-proxy-v1 = on
...
$ service hitch start
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16. Massive Storage Engine (MSE)
$ mkfs.mse -s /var/lib/varnish/mse/store,5GB
-b /var/lib/varnish/mse/book,50MB -p big_alloc=5MB
Creating data stores in file '/var/varnish/mse/store'
Cooking the books in file '/var/lib/varnish/mse/book'. This may take a
while ...
Creating 209661 spare nodes
Creating 209661 spare nodes
Finished
Varnish Plus Massive Storage Engine data files successfully created.
Varnish Plus stevedore argument:
varnishd -s mse, /var/lib/varnish/mse/store,/var/lib/varnish/mse/book
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17. VCS Configuration
sub vcl_deliver {
std.log("vcs-key:ALL");
std.log("vcs-key:HOST/" + req.http.Host);
std.log("vcs-key:URL/" + req.http.Host + req.url);
std.log("vcs-key:CONTENT/" + req.http.Host + "/" +
regsub(resp.http.Content-Type, ";.*", ""));
std.log("vcs-key:SESSIONS/" + req.http.veid);
}
/etc/varnish/cdn.vcl
DAEMON_OPTS="138.197.97.165"
/etc/varnish/vstatdprobe.params
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18. Cedexis Configuration: Radar
Radar
- Deploy “tag” in Web pages to start
testing
- Place “Test-Objects” to test each
deployment (Server/Cluster)
- Configure Cedexis Portal to Monitor
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19. Cedexis: Configuring Openmix
Decide on HTTP or DNS “Decisions”
Create Application
- Forms Driven (Portal)
- Custom JS (ECMA5)
- Common Code base for HTTP and DNS.
- http://developers.cedexis.com
Deploy
- Via Portal “2 Stage” Publish
Go-Live
- DNS - CNAME to Cedexis host (2-01-5024-
0003.cdx.cedexis.net)
- HTTP - Integrate API into a CMS or Player.
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20. Demo
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21. Take away
● Building your private CDN is not rocket science with Varnish Extend
● Roll it out gradually: keep risks controlled and low!
● Gain consumer power by combining Varnish and CDN offerings
● Gain control on the delivery of your content with minimum overhead and
complexity
● Maximize hardware resource utilization
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23. Varnish High Availability (VHA)
Varnish 1
VHA
Varnish 2
VHA
1
2
3
4
5
6
7
8
Client
1. Client request
2. Backend request
3. Backend response
4. VHA notices a new cached
object
1. Client response
2. Signals replication request
3. Peer request
4. Peer response
5. Object replicated
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Backend
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24. Varnish High Availability (VHA)
sub vcl_recv {
call vha_backend_selection;
}
sub vcl_hit {
call vha_skip_grace;
}
sub vcl_deliver {
call vha_clean_headers;
}
/etc/varnish/cdn.vcl
$ vha-generate-vcl --token 9ad34eccb > /etc/varnish/vha.vcl
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25. Varnish High Availability (VHA)
ENABLE=1
NAME=singapore-01
DAEMON_OPTS="-N /etc/varnish/nodes.conf -m singapore-01
-s /var/lib/vha-agent/vha-status -T 9ad34eccb"
vha-agent.params
singapore-01 = https://cdn-singapore-01.varnish-software.com
singapore-02 = https://cdn-singapore-02.varnish-software.com
/etc/varnish/nodes.conf
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26. Numerous Possibilities for Load-Balancing
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27. Extending Intelligence with Fusion
- A Service that takes 3rd Party Data for use
within an Openmix Application
- Pre-built Interfaces with:
- CDN’s
- APM (Monitoring)
- Server Architectures
- Can pull Bandwidth, Usage etc from suppliers
- Custom ingest also possible with Fusion
Custom (Anything text based)
- Business Metrics like cost, commit
- Custom Technical Metrics
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28. DNS or HTTP
DNS
- Common Method of Integration for
WebSites/Applications
- DNS CNAME integration
- Decision made at Resolver Level
- Fully Transparent to end-user.
HTTP
- Usually used for Video
- API based Integration
- Points to “Best” delivery Architecture
- Ordered List or Single Provider response
- Decision Made at requestor (Client) IP level.
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29. Test material
● DASH player from https://github.com/Dash-Industry-Forum/dash.js/
● DASH videos from http://dash.edgesuite.net/dash264/TestCases/5a/
● Player Demo: https://cdn.varnish-software.com/dash.js/samples/dash-if-
reference-player/
● Load-balancing script examples: developers.cedexis.com
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