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Simple infrastructure DNS service inside Amazon Cloud automated by Ansible, created @ BaseCRM
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DNS CLUSTERAutomated Internal DNS Service with Amazon VPC integration
Sławomir Skowron System Engineer (DevOps Team) [email protected]
2013
DevOps Krakow #Meet 1
DNS INTRODUCTION
• Domain Name System is hierarchical and distributed naming system
• Essentially name service for TCP/IP networks
• Allow IP address resolution mechanism
• Adds tree based domain name space,
• Name space is sub-divides into zones and start with root zone
• One of the first NoSQL key-value database
WHAT IS DNS ?
Tree hierarchical structure starting from . (root)
NAMESPACE
ZONESDelegated part of domain name space for administrative responsibility.
DOMAIN NAME SERVERSSoftware on servers that store, manage and serve information about own part of domain namespace called zone
Two types of servers: master and slave
DNS QUERIES
• Recursive - querying other servers until positive response
• Iterative - add local response (cache, local zone) or give info where to look for it.
Two type of external queries: Recursive and Iterative
Cached Queries - DNS Cache - improve latency and throughput
DNS AS A SERVICE INSIDE AMAZON CLOUD
AMAZON EC2 DNS (VPC) PROBLEMS
• Route-53 (right now) is not supporting internal DNS domains
• Amazon VPC Internal DNS support only ec2.internal domains
• Amazon VPC DHCP in default support only AWS DNS
Our own DNS Service
USE CASE
• Available only in LAN and through VPN
• Only A and SRV - infrastructure DNS
• Resolv local and forward if not exist
• No zone transfer, No slaves, No masters
• Updates are simple, secure and fast
Our own DNS Service
SOLUTION
• Clustering for High Availability and Performance
• Integration with our VPC’s DHPC
• Availability in every Amazon Region
• Caching
• Fully Automated and Integrated with Instance Provisioning
• Support for our name space
Our own DNS Service
HIERARCHYHierarchy of private DNS at BaseCRM
DNSCLUSTER RELEASE 1.0
ALMOST :)
SOLUTION• Puppet 3 as Configuration Management solution
• Puppet Hiera, PuppetDB integration
• TheForeman - http://theforeman.org/
• Foreman integrates with BIND
• Unbound as DNSCluster core - local zones, forwarder, cache
• Git for store zones and versioning
DNSCLUSTERIntegration with Puppet and TheForeman
WHAT’S WRONG WITH PUPPET ?
• Puppet is slow
• Hard and slow flow developing with Puppet
• Hard to integrate on running machines before puppet.
• PuppetDB is ok but it’s not scalable enough
• Everything go through Foreman and BIND in our case
PUPPET
ANSIBLERadicaly simple IT orchestration
ANSIBLE• Minimal setup - Python + Libs - pip install ansible
• Use existing auth (root, sudo) on SSH as default transport or accelerated mode
• Ad-hoc operations built in
• async, sync and parallel operations
• Predictable, easy to expand (plugins, connectors, filters, modules)
• Use powerful templates in jinja2
• outputs in json,
• configure in yaml
ANSIBLE @ BASE• Two months of work all in GIT
• 15 playbooks (Universal Flow)
• 25 roles
• 180 yaml files
• 52 template
DNSCLUSTER RELEASE 2.0
SOLUTION• Ansible
• Unbound as DNSCluster core - local zones, forwarder, cache
• Git for store zones and versioning
• Amazon VPC DHCP integration - under development
• ETCD integration - under development
Keep it simple, stupid Core Thinking
KISS
IMPROVEMENT• Simple workflow
• Faster development
• Fast Deploy with low memory/cpu consumption
• No central DB
• All data are stored in 3 places and can be restored from running machines
• Work as push or pull workflow
• Integrated with VPC DHCP if new DNSCluster is created
KISS as core thinking
DNSCLUSTER 2.0Flow for DNSCluster Client
DNSCLUSTER 2.0 - MULTI-REGIONS
DNS CLUSTER PERFORMANCE
DNSCLUSTER PERFORMANCE
1 500 10000
500
1000
1500
2000
2500
AWS DNS
DNSCLUSTER 1 node (1 cpu core – ec2.x1.small)
UNBOUND local cache (forwarders: 3 dnscluster nodes – 3 x ec2.x1.small) 1 pass – 1 unbound thread
UNBOUND local cache (forwarders: 3 dnscluster nodes – 3 x ec2.x1.small) 2 pass – from cache – 1 unbound threads
UNBOUND local cache (forwarders: 3 dnscluster nodes – 3 x ec2.x1.small) 2 pass – from cache – 2 unbound threads
Concurrency
QPS
Queries per second / Concurrency
DNSCLUSTER PERFORMANCELatency / Concurrency
1 500 10000
0.02
0.04
0.06
0.08
0.1
0.12
AWS DNS
DNSCLUSTER 1 node (1 cpu core – ec2.x1.small)
UNBOUND local cache (forwarders: 3 dnscluster nodes – 3 x ec2.x1.small) 1 pass – 1 unbound thread
UNBOUND local cache (forwarders: 3 dnscluster nodes – 3 x ec2.x1.small) 2 pass – from cache – 1 unbound threads
UNBOUND local cache (forwarders: 3 dnscluster nodes – 3 x ec2.x1.small) 2 pass – from cache – 2 unbound threads
Concurrency
Late
nsy
[sec
onds
]
SOON / NEXT TIME ?
Monitoring and Alertingsecond element for our auto scaling
Ansible Universal Template Flow Created @ Base for simple consistent create/destroy instances
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