For those interested, detailed description of BUK SAM Systems and the corresponding A-A missiles.
9K37/9K37M1/9K317 Buk M1/M2 / SA-11/17 Gadfly/Grizzly / C????????? ???????? ???????? ???????? 9?37/9?317 ??? ?/?1/?2
However, some discussions are misleading, assuming that a whole anti-aircraft complex has been involved in MH017 shot-down together with a complicated chain of command. In it's logic any single isolated unit (TELAR - launcher and radar) is capable of acquiring, targeting and engaging targets individually.
Individual units (erector/launcher) may be fitted with own radars, but IMO that's not mandatory for a successful launch against a big surface rectilinear-track and constant relatively low speed target. The missile carrier is equipped also with an IR seeker and an electro-optical sighting system by which means the crew may initiate a launch without radar aid - the so-called SACLOS logic (semi-automatic command to line-of-sight). By those optical means, as well, in case of radar jam the crew can track the target and up-link corrections to the missile through radio-command. On top, both SA 11/17 are equipped with onboard radars (monopulse semiactive or active - the newest type - radar homing seeker). It's not clear they are 'fire-and-forget' - capable missiles (like the ex-Soviet 'cousin' SA-19) but it's not unusual for such equipment once airborne to seek, lock-on and track a target on its own.
Adding that the shot-down occurred in daylight and good visibility is plausible that the launch was initiated in a rush, at sight, with no proper preparation and id.