Serf@devops pune
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Transcript of Serf@devops pune
Target Audience
Having some knowledge of cluster environment
Managed Clusters environment
Eager to Learn SERF
SERF (By Hashicorp) OPEN SOURCE
Decentralized
Fault-tolerant
Highly Available
Uses Gossip Protocol to communicate with nodes
Extremely Light Weight (5-10 MB Memory Footprint)
Available for Linux, Mac OS X, and Windows
SERF USED FOR
Cluster Membership Management
Failure Detection and Recovery
Event Propagation
Orchestration
Installation Download SERF from https://www.serfdom.io/downloads.html Unzip and put binary in /usr/local/bin or /usr/bin folder (in LINUX)
SERF AGENT Core process
Maintains membership information
Propagates events
Invokes event handlers
Detects failures
Run on every node that is part of cluster
Custom Event Propagation
Dispatches a custom user event
Nodes in the cluster listen custom events
Reacts to them
Execute Event Handlers
Doesn’t send response back to originator
SERVICE ORCHESTRATION Dispatches a query
Nodes in the cluster listen query
Reacts to them
Execute Event Handlers
Send response back
Gathering Responses at originator
USE CASES Webservers and load balancers
Memcached and Redis clusters
Triggering deployments
Updating DNS records
Simple Observability
A Building Block for Service Discovery
DEMO Setting up high availability configuration(Webserver)
Serf1
eth0172.26.126.82
VIP172.26.126.84
Apache
Serf2
eth0172.26.126.74
SERF AGENT SERF AGENT
Apache
GOSSIP PROTOCOL
Limitations
Under heavy development
Events are eventually consistent
Payload size is limited
Queries may not be delivered to all nodes
Responses and acknowledgements may not be receive by query originator