Creating a bootable USB for Centos on Mac OS X

I’m a huge Ubuntu fan. However, most of my ‘day job’ work requires CentOS or RHEL, thus I commonly have to re-image my on premise Cloud with the latest and greatest CentOS. My servers are 3 Rackables by SGI, two with more CPU & Memory and one (the controller node) with tons of Disk (12x1TB RAID 10) and then for off-premise I use Digital Ocean who has a fantastic product. Most modern servers do not have a CDROM and neither do my on premise systems. Therefore, I need to place the CentOS image on a USB drive so I can re-image my lab. Here are the steps do that on Mac OS X.

List the current Disks & Partitions

➜  ~  diskutil list
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI                         209.7 MB   disk0s1
   2:          Apple_CoreStorage                         499.4 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Macintosh HD           *499.1 GB   disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 GB     disk2
   1:                  Apple_HFS Untitled                1.9 GB     disk2s1
➜  ~

My USB drive is the 2GB drive at the bottom, we need to unmount that

➜  ~  diskutil unmountDisk /dev/disk2
Unmount of all volumes on disk2 was successful
➜  ~

Next we copy the CentOS image onto the unmounted USB disk.

➜  ~  sudo dd if=/Users/jriedel/Downloads/CentOS-7-x86_64-Minimal-1503-01.iso of=/dev/disk2
1302528+0 records in
1302528+0 records out
666894336 bytes transferred in 620.521343 secs (1074732 bytes/sec)
➜  ~

When that’s gets done your Mac will pop up a window asking you to initialize the drive, ignore that. Remove it, and your ready to boot off this USB!



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