CPG_OVERVIEW(3)

💖 CPG_OVERVIEW — bestie, let's talk about cpg_overview 💖

okay so real talk, this is a page from the Corosync Cluster Engine Programmer's Manual, and it's literally just cpg_overview — which is, and I cannot stress this enough, the overview of the CPG library. No functions to call, no flags to set. Just vibes and ✨ context ✨. Sit with me.

🌸 NAME 🌸

cpg_overview — CPG library overview. That's it, that's the name. Short, sweet, iconic. 💅

🦋 OVERVIEW 🦋

So the CPG library ships with the corosync project. It exists so you can build distributed applications that keep their whole act together even when the cluster is going through it — partitions, merges, faults, the entire chaotic era. Your app stays functional, periodt. 💀➡️👑

The library gives you a mechanism to:

• handle abstraction for multiple instances of a CPG library in one application 👯‍♀️ (yes, more than one, in one app, she contains multitudes)
• join one or more groups 🫶
• leave one or more groups 👋
• Deliver messages to members of that group 💌
• Deliver configuration changes 📢
• Iterate members of groups 🔁

Like. That's a whole friendship group management system and honestly? Obsessed.

🔥 SECURITY 🔥

okay this part matters so listen up:

If encryption is enabled in corosync.conf, the CPG library will encrypt and authenticate message contents. ✨

⚠️ bestie this is the important bit ⚠️ Applications must run as the ais user to be validated by corosync on IPC connection. Otherwise they will be unable to access the corosync services. Not "slower", not "degraded" — unable. So run as ais, okay? Do not test me on this one. 🙈

🌈 SEE ALSO 🌈

the whole friend group, in order, no gatekeeping:

• cpg_overview(3)
• cpg_initialize(3)
• cpg_finalize(3)
• cpg_fd_get(3)
• cpg_dispatch(3)
• cpg_join(3)
• cpg_leave(3)
• cpg_mcast_joined(3)
• cpg_model_initialize(3)
• cpg_membership_get(3)
• cpg_zcb_alloc(3)
• cpg_zcb_free(3)
• cpg_zcb_mcast_joined(3)
• cpg_context_get(3)
• cpg_context_set(3)
• cpg_local_get(3)
• cpg_iteration_initialize(3)
• cpg_iteration_next(3)
• cpg_iteration_finalize(3)

and that's the whole page, bestie 🎀 this one came out of the corosync Man Page, dated 2009-4-15, and it's filed under CPG_OVERVIEW(3). ancient but still eating. 💜 mwah, go read cpg_initialize(3) next ✨