Is this build any good?

https://metabattle.com/wiki/Build:Necromancer_-_Minion_Master

I'm new to GW2, was wondering if this build is good for pve, dungeons, and raids..... Do dungeons and raids have bosses? and is this build good for everything?

First of all, your question would be better suited in the Necromancer subforum: https://en-forum.guildwars2.com/categories/necromancer

On your question:This build is an outdated PvP build. Will it get you along in open world PvE? It will, but to be fair- everything will. Will it get you through Dungeons? Probably, but be aware of whom you run them with. Most random people will expect you to run some sort of efficient "meta'ish" build.Is this good for fractals or raids? Short answer: no. Long answer: fractals and raids are endgame content and unless you do them with friends, that are willing to take you with them while running some weird niche build, you'll probably get kicked out of the parties more often than not. Finding a random party for those game mods as a necromancer can be tough already and it will only get harder if you bring along such a build.tl;dr: either find some friends that are ok with the way you play or forget this build and rather take a look at the current meta-builds.

Your build is only good for open world PvE. When it comes to fractals, raids, PvP and WvW is really not that good. Since you're using mostly minions then it'll only help you in open world PvE content. Also, since you're asking questions about the Necromancer, post in the Necromancer subforum.