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Browse the latest tutorials, guides, and practical examples across Linux, DevOps, security, databases, and programming on GoLinuxCloud.

Explore the latest tutorials and guides across Linux, DevOps, programming, and more.

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3098 articles

Blog illustration with latest articles, tutorials, guides, and how-to content across Linux and DevOps topics
devops

What Is Single Sign-On (SSO) and How Does It Work?

Learn what single sign-on is and how SSO works in the browser: IdP vs application sessions, SAML and OIDC, trust between apps and the IdP, and why logout is not always universal.

Deepak Prasad13 min read
devops

Identity Provider (IdP) vs Service Provider (SP)

Learn the difference between an identity provider (IdP) and a service provider (SP), how they work together in SSO, SP-initiated versus IdP-initiated login, and how SAML terms map to OIDC OpenID Provider and Relying …

Deepak Prasad11 min read
devops

OAuth 2.0 vs OpenID Connect vs SAML: What’s the Difference?

Compare OAuth 2.0, OpenID Connect, and SAML 2.0 by purpose, tokens, flows, and when to choose each protocol, including how Keycloak supports OIDC and SAML clients.

Deepak Prasad15 min read
devops

Create and Manage Users in Keycloak: Admin Console and API

Create and manage local Keycloak users—set and reset passwords, required actions, enable and disable accounts, search users, and automate with Admin REST API and kcadm on Keycloak 26.7.3.

Deepak Prasad11 min read
devops

Keycloak Custom User Attributes with User Profile

Learn how to add custom user attributes in Keycloak with User Profile—create a department field, set values on users, show fields on registration forms, add validation and permissions, and map attributes into tokens.

Deepak Prasad11 min read
devops

Keycloak start vs start-dev: Development and Production Modes

Learn the difference between Keycloak start and start-dev, including HTTP, hostname, HTTPS, cache and database behavior, and when to use each mode.

Deepak Prasad10 min read
devops

Keycloak Protocol Mappers: Add Custom Claims to Access and ID Tokens

Add custom claims to Keycloak access and ID tokens with protocol mappers. Map user attributes, groups, and audience on Keycloak 26.7.3, then verify with a decoded JWT.

Deepak Prasad13 min read
devops

Keycloak Realm Roles vs Client Roles vs Composite Roles

Compare Keycloak realm roles, client roles, and composite roles—create employee and order-reader, inspect realm_access vs resource_access in access tokens, and troubleshoot roles missing from JWTs on Keycloak 26.7.3.

Deepak Prasad12 min read
devops

Keycloak Public vs Confidential Clients: Which Should You Use?

Learn the difference between public and confidential clients in Keycloak, which client type to use for SPAs, mobile apps and server-side applications, and how Client authentication, PKCE and client secrets fit together.

Deepak Prasad9 min read
devops

Configure Keycloak with PostgreSQL

Configure Keycloak 26.7.3 with PostgreSQL using KC_DB and JDBC settings, start production mode against an external database, and prove realm data survives Keycloak container replacement on Podman or Docker.

Deepak Prasad13 min read
devops

Build an Optimized Keycloak Container Image with kc.sh build

Learn how to build an optimized Keycloak container image with kc.sh build, separate build-time and runtime configuration, and start it with start --optimized.

Deepak Prasad11 min read
devops

Configure Keycloak Behind a Reverse Proxy

Run Keycloak behind Nginx or HAProxy with edge, re-encrypt, or passthrough TLS, set KC_PROXY_HEADERS and trusted addresses, enable PROXY protocol when needed, and fix 403, wrong scheme, and wrong OIDC issuer issues on …

Deepak Prasad12 min read
devops

Configure Keycloak HTTPS/TLS with SSL Certificates

Enable Keycloak HTTPS on port 8443 with PEM or PKCS12 certificates, set KC_HOSTNAME to the full public URL, reload certificates without restart, tune TLS protocols, and verify the OIDC issuer on Keycloak 26.7.3.

Deepak Prasad9 min read
devops

Keycloak Groups: Create Nested Groups and Inherit Roles

Learn how Keycloak groups work, create nested groups, add users, assign realm and client roles, and understand role and attribute inheritance.

Deepak Prasad10 min read
devops

How to Configure Keycloak with Environment Variables (KC_*)

Learn how Keycloak KC_* environment variables work, how to set them in Docker, Podman, Compose, and Linux, and how to fix values that appear ignored.

Deepak Prasad17 min read
devops

How to Automatically Assign Roles and Groups to New Users in Keycloak

Learn how to automatically assign Keycloak default roles and default groups to new users, verify inheritance in the Admin Console, and understand what happens to existing accounts on Keycloak 26.7.3.

Deepak Prasad12 min read
devops

How to Persist Keycloak Data in Docker and Podman

Learn which Keycloak Docker and Podman volumes to persist: mount /opt/keycloak/data for start-dev H2 data, persist the database for external PostgreSQL, and understand restart vs container recreate.

Deepak Prasad18 min read
devops

Keycloak Configuration with keycloak.conf: Examples & Precedence

Learn how Keycloak loads keycloak.conf, where the file lives, how CLI flags and KC_* environment variables interact, configuration precedence, ${…} interpolation, build-time vs runtime options, and how to verify settings …

Deepak Prasad13 min read
devops

Run Keycloak as a systemd Service on Linux

Run Keycloak 26.7.3 as a Linux systemd service after a ZIP install: dedicated keycloak user, minimal keycloak.conf, unit file directives, enable at boot, journalctl logs, and common startup failures.

Deepak Prasad14 min read
devops

Install and Run Keycloak with Podman

Install Keycloak 26.7.3 with rootless Podman on RHEL-family Linux, start-dev on port 8080, Podman volumes and SELinux :Z mounts, container logs, and Quadlet persistence paths.

Deepak Prasad15 min read
devops

How to Install Keycloak on Linux

Install Keycloak on Linux using the official distribution, with Java runtime setup for Ubuntu, Debian, RHEL, Rocky Linux and AlmaLinux, first admin login, and start-dev verification.

Deepak Prasad12 min read
devops

Install Keycloak on Kubernetes with the Keycloak Operator

Install Keycloak 26.7.3 on an existing Kubernetes cluster with the Keycloak Operator, PostgreSQL, database Secrets, a Keycloak custom resource, bootstrap admin login, and kubectl port-forward to the Admin Console.

Deepak Prasad18 min read
devops

Install Keycloak with Helm: Chart Options vs Keycloak Operator

Compare Keycloak Helm chart options with the official Operator, then install Keycloak 26.7.3 with the codecentric keycloakx chart, PostgreSQL, bootstrap admin credentials, helm upgrade, and uninstall on Kubernetes.

Deepak Prasad19 min read
devops

Keycloak Docker Compose with PostgreSQL

Run Keycloak 26.7.3 with PostgreSQL using Docker Compose on Linux — compose.yaml, KC_BOOTSTRAP_ADMIN variables, health checks, persistent volumes, Admin Console login, and PostgreSQL verification.

Deepak Prasad15 min read
linux

How to Install Docker on RHEL

Install Docker Engine Community (Docker CE) on RHEL 8, 9, and 10 from the official DNF repository, enable docker.service, verify with hello-world, optionally add the docker group, upgrade, and uninstall cleanly.

Omer Cakmak8 min read
devops

How to Install Keycloak with Docker

Install Keycloak 26.7.3 with Docker Engine using the official Quay image, start-dev, bootstrap admin, port 8080, Docker logs, configuration delivery, first login, and container restarts.

Deepak Prasad12 min read
devops

Keycloak Clients Explained: OIDC, SAML, URLs, and Client Settings

Learn what a Keycloak client is, how realm clients differ from users, OIDC vs SAML client types, client ID vs internal UUID, redirect URIs, web origins, authentication settings, and common client errors on Keycloak …

Deepak Prasad13 min read
devops

Keycloak Client Scopes: Default, Optional & Dedicated Explained

Learn how Keycloak client scopes work — Default, Optional, and Dedicated scopes, creating and assigning scopes, and verifying JWT claims with before-and-after token examples.

Deepak Prasad17 min read
devops

Authentication vs Authorization: Differences and Examples

Learn how authentication and authorization differ, with examples from login, API bearer tokens, roles, OAuth, OpenID Connect, and HTTP 401 versus 403 responses.

Deepak Prasad10 min read
devops

What Is IAM? Identity and Access Management Explained

Learn what identity and access management (IAM) is, how authentication and authorization differ, and how SSO, MFA, provisioning, federation and access lifecycle management work together.

Deepak Prasad13 min read