Description of problem:
If we use an encrypted PV to boot from and at the same time want to mount an ecrypted iSCSI disk, we add both these entries to /etc/crypttab. Now while non-iSCSI disk is available for cryptsetup in very early booting stages, iSCSI is only available after network starts (later than /etc/crypttab is processed). This introduces a delay in boot. 

Is an option similar to fstab's _netdev available? This would tell cryptsetup to process this concrete line later, when iSCSI is ready

Version-Release number of selected component (if applicable):


How reproducible:
always

Steps to Reproduce:
1. enter both boot disk / LV and an iSCSI disk in /etc/crypttab
2. boot

Actual results:
cryptsetup will start (and process /etc/crypttab) before iSCSI has established connection with the target (network is not ready). This introduces delay in boot and the volume is not mounted.


Expected results:
Have cryptsetup distinguish between items it needs to process in early stages of boot (rootfs) and those that will be mounted later via iSCSI. The desired effect is similar to _netdev parameter in fstab.