HashiCorp Certified: Consul Associate 2022

Explore the basics of Consul, a service mesh that provides a control plane for service discovery, health checks, a key-value store, and secure service communication across microservices.

Explore the lab infrastructure for consul, featuring a simple single-binary installation across platforms and a digitalocean-based multi-server setup to practice service discovery, health checks, and mutual TLS.

Install Consul on Linux by downloading the single binary, configuring the official HashiCorp repository, and running three commands to install the package, with cross-platform support for Linux, Mac, and Windows.

learn how to run consul in dev server mode for local development, explore its in-memory behavior, and secure gui access via firewall rules on port 8500.

Explore the basics of Consul architecture, detailing the server and client roles, the agent running on each node, and how data centers enable high availability and health checks.

Join a Consul client to a server in dev mode, understand leader and follower roles, and configure join, bind, and data directory to enable cluster communication.

Learn to start the console agent from a configuration directory, mapping cli options to json or acl files like start_join and bind_addr, and verify nodes.

Describe two Consul agent leave behaviors: graceful exit and force removal. Compare outcomes: graceful exit informs the cluster before leaving; force removal leaves unnotified, triggering replication retries.

Learn how to run Consul in server mode for production, using flags like server, bootstrap, node, bind, and data, plus configuring the config directory and UI.

Learn to integrate systemd with consul by using a service file to run the consul agent as a dedicated user, with proper config and data directories.

Explore the basics of service discovery with consul, using a central registry to dynamically locate services and resolve their IP addresses and ports, reducing latency.

Learn how consul's central registry tracks services, IPs, and ports by creating a service definition file to register services and using DNS (port 8600) with dig to locate them.

Learn how Consul monitors services with application and system health checks, including script, http, and tcp checks; verify health with exit codes and centralized dashboards.

Explore how Consul's key-value store holds service configuration and metadata via gui or api, with cli commands to put, get with recurse, update, and delete keys, up to 512 kb.

Explore how the Consul watch feature monitors changes in the key-value store, triggers external scripts, and responds to updates on keys, prefixes, services, nodes, checks, and events with practical examples.

Learn how the Consul template binary watches a key-value in Consul and automatically updates an output file using a template, with configurable source, destination, and command.

Explore env console, a tool that fetches key-value data from HashiCorp console and vault into environment variables for docker and other apps.

Learn how Consul Connect secures service-to-service communication with mutual TLS and authorization using two local proxies between a front-end and a back-end service, enforcing intended access rules.

Implement consul connect from scratch with nginx front end on 8080 and back end on 9080, using sidecar proxies and dev-mode agents, and enforce authorization with intentions.

Explore how Consul intentions control service communication with connect, using CLI commands to create, deny, check, and match rules, and learn how precedence determines access.

Explore sidecar proxy support in Consul Connect with Envoy as a first-class sidecar, enabling traffic splitting and load balancing with http2, gRPC, and layer seven traffic observability.

Uncover how Consul acl secures the user interface, api, and cli by enabling acl, creating a bootstrap token, and using an environment variable to authenticate for production deployments.

Explore HashiCorp ACL rules by connecting tokens to policies and rules, with resources like key value stores and wildcards to control read, write, and deny access.

Understand ACL rules in Consul by grouping policies into a team lead rule, attach demo policy and deny Samsung policy, and apply the rule to a token to enforce access.

Learn how anonymous tokens grant read-only access to services, nodes, and key value when no bearer token is provided. Note that these tokens cannot be deleted.

Enable ACLs on agents by applying a deny-based policy, review logs for blocked actions, and create an agent token policy with node write and service read permissions.

Gain a high level overview of the gossip protocol, explaining peer-to-peer data dissemination using random targets, infection-style propagation, and lower overhead than non-gossip approaches.

Enable consul gossip encryption to secure gossip traffic on tcp/udp port 8301, preventing plain-text capture; generate a cryptographic key with consul key gen and configure it via the encrypt parameter.

Learn how to enable gossip encryption in an existing data center by following a four-step process: generate a key gen, set encrypt verify incoming/outgoing to false, then true, and restart.

Discover how to rotate consul gossip encryption keys with the console key ring: generate, install, promote, and remove keys, while noting join-time encrypt use and local keyring persistence.

Demystifies asymmetric key encryption using public and private keys for encryption and decryption, with examples like email, SSH login, and TLS as widely used protocols.

Explain how https builds on http by using tls to encrypt traffic, generate a temporary symmetric key with a public key from a certificate, and verify trusted certificate authorities.

Learn to secure Consul RPC traffic on port 8300 with TLS by creating a private CA, issuing a server certificate, and configuring server and client for encrypted communication.

Configure TLS in Consul with verify incoming, verify outgoing, and verify server hostname. Learn to manage CA files, server certificates, and private keys for secure server authentication and client verification.

Explore how application programming interfaces enable intercommunication between software, with interfaces delivering documented request and response structures, authentication tokens, and weather data examples.

Explore Consul's http api, using v1 endpoints for catalog and key value resources, with curl and browser testing, and understand acl headers for authentication.

Understand how split brain occurs when two masters write to storage during a network partition. Learn how an odd-number quorum with votes prevents split brain and selects a new master.

Learn to build a highly available Consul cluster with three servers using bootstrap-expect and quorum, auto leader election, and join commands to preserve data during failures.

Explore how consul enables a multi data center architecture by connecting data centers across clouds and on premise, using van gossip and rpc forwarding to access remote resources.

Explore how prepared queries run at the data center level to return the latest service IP addresses, enabling version-specific results and cross data center failover.

Create two service versions and configure a prepared query to route traffic to version 1 or version 2. Update the prepared query endpoint to switch and verify via api calls.

Implement prepared query failover by locating the database service in the local data center and failing over to the Singapore data center when unavailable, with dns resolving to 5080 or 6080.

Explore backup and restore in Consul using snapshots, capturing key value entries, service catalog, prepared queries, sessions, and ACLs; perform save and restore while noting caveats and best practices.

Explore how the console autopilot pattern automates startup, shutdown, scaling, and recovery, limits outages from dead servers, and manages server stabilization time for voting members.

Explore methods to automatically join Consul servers, including join, retry join, and cloud auto join, with guidance on handling unavailable servers and configuring retry intervals.

Explore cloud auto join, a unified interface using the go Discover library to automatically join a console data center via AWS EC2 tagging and metadata.

Explore Consul logs with console monitor to follow running agent logs at various levels, and use console debug to capture a time-bound archive for troubleshooting, including cluster and host details.

Explore Consul's reloadable configuration, learn which items reload on a reload (services, ACL tokens, checks, http client address, log level, node metadata, watches) and when to use reload over restart.

Explore consul enterprise, including audit logging, automated backups, namespaces, redundancy zones, automated upgrades, and enhanced read scalability, plus steps to subscribe for a 30-day trial license.

Consul enterprise namespaces separate teams within an organization, enabling conflict-free access to shared console data centers and namespace-specific keys, values, and granular permissions.

Explore practical namespace implementation in Consul, including GUI and CLI creation, ACLs, key-value, and namespace-specific services with DNS-based discovery.

Automate enterprise backups with the console snapshot agent, rotating snapshots and securely syncing to offsite storage (S3, Azure, GCP) via a systemd service that runs in the background.

Implement fault tolerance with redundancy zones by configuring three voter and three non-voter Consul instances, tagging each node with zones and enabling autopilot to reallocate leadership when a voter fails.

Navigate HashiCorp exams by mastering multiple-choice formats, online proctoring, registration steps, costs, and system requirements for a smooth test experience.

Master dev mode with the command console agent - dev for local testing, and prepare for server mode questions using flags like server, bootstrap, bind, datadir, and config dev flag.

Learn console connect for service-to-service communication with mutual tls and a layer four proxy, covering destination name, local bind port, upstream, acls, tokens, and intentions.

Cover essential Consul exam pointers on key value operations, API encoding, template and watch features, prepared queries, failover logic, backups, enterprise namespaces, and port basics.

Master exam-ready pointers for HashiCorp Consul, covering certificate distribution, gossip encryption, join methods, env console, sidecar proxy with envoy, reloadable config, monitoring, debugging, and disaster recovery.