Update based on suggestions: narrow which devices we're targeting, us…

…e the PATH for binaries and link to scripts rather than recreating them.

999-aws-ebs-nvme.rules

@@ -1 +1 @@
-SUBSYSTEM=="block", KERNEL=="nvme[0-9]*n[0-9]*", ATTRS{model}=="Amazon Elastic Block Store", PROGRAM+="/usr/local/sbin/ebs-nvme-mapping.sh /dev/%k" SYMLINK+="%c"
+SUBSYSTEM=="block", KERNEL=="nvme[0-26]n1", ATTRS{model}=="Amazon Elastic Block Store", PROGRAM+="/usr/local/sbin/ebs-nvme-mapping.sh /dev/%k" SYMLINK+="%c"

README.md

@@ -282,7 +282,7 @@ So, let's trim the trailing spaces for a viable block device name.
 /dev/xvdf
 ```
 
-We now have our desired block device name. 
+We now have our desired block device name.
 
 ## The Hacky Solution
 
@@ -378,52 +378,14 @@ your configuation.
 
 I've picked `ATTRS{model}`.
 
-Let's combine what we've found into a shell script...
-
-```
-[ec2-user@ip-10-81-66-128 ~]$ cat <<EOF> ebs-nvme-mapping.sh
-> #!/bin/bash
-> 
-> if [[ ! -x /usr/sbin/nvme ]]; then
->   echo "ERROR: NVME tools not installed." >> /dev/stderr
->   exit 1
-> fi
-> 
-> if [[ ! -b ${1} ]]; then
->   echo "ERROR: cannot find block device ${1}" >> /dev/stderr
->   exit 1
-> fi
-> 
-> # capture 32 bytes at an offset of 3072 bytes from the raw-binary data
-> # not all block devices are extracted with /dev/ prefix
-> # use `xvd` prefix instead of `sd`
-> # remove all trailing space
-> nvme_link=$( \
->   /usr/sbin/nvme id-ctrl --raw-binary "${1}" | \
->   /usr/bin/cut -c3073-3104 | \
->   /bin/sed 's/^\/dev\///g'| \
->   /bin/sed 's/^sd/xvd/'| \
->   /usr/bin/tr -d '[:space:]' \
-> );
-> echo $nvme_link;
-> EOF
-[ec2-user@ip-10-81-66-128 ~]$ sudo install -m 0755 ebs-nvme-mapping.sh /usr/local/sbin/
-[ec2-user@ip-10-81-66-128 ~]$
-```
+Let's combine what we've found into a [shell script](ebs-nvme-mapping.sh), and a [udev rule](999-aws-ebs-nvme.rules)...
 
-...and a udev rule...
+...and finally reload the `udev` rules and trigger it...
 
 ```
-[ec2-user@ip-10-81-66-128 ~]$ cat <<EOF> 999-aws-ebs-nvme.rules
-> SUBSYSTEM=="block", KERNEL=="nvme[0-9]*n[0-9]*", ATTRS{model}=="Amazon Elastic Block Store", PROGRAM+="/usr/local/sbin/ebs-nvme-mapping.sh /dev/%k" SYMLINK+="%c"
-> EOF
-[ec2-user@ip-10-81-66-128 ~]$ sudo install -m 0644 999-aws-ebs-nvme.rules /etc/udev/rules.d/
-[ec2-user@ip-10-81-66-128 ~]$
+[ec2-user@ip-10-81-66-128 ~]$ sudo udevadm control --reload-rules && udevadm trigger
 ```
 
-`udev` will automatically reload rules upon changes to files in the rules directory. So we're locked
-and loaded.
-
 Now, when we attach and detach EBS volumes, our shell script will run.
 
 ## A Test Run

ebs-nvme-mapping.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 # To be used with the udev rule: /etc/udev/rules.d/999-aws-ebs-nvme.rules
 
-if [[ ! -x /usr/sbin/nvme ]]; then
+if [[ ! -x nvme ]]; then
   echo "ERROR: NVME tools not installed." >> /dev/stderr
   exit 1
 fi
@@ -16,10 +16,10 @@ fi
 # use `xvd` prefix instead of `sd`
 # remove all trailing space
 nvme_link=$( \
-  /usr/sbin/nvme id-ctrl --raw-binary "${1}" | \
-  /usr/bin/cut -c3073-3104 | \
-  /bin/sed 's/^\/dev\///g'| \
-  /bin/sed 's/^sd/xvd/'| \
-  /usr/bin/tr -d '[:space:]' \
+  nvme id-ctrl --raw-binary "${1}" | \
+  cut -c3073-3104 | \
+  sed 's/^\/dev\///g'| \
+  sed 's/^sd/xvd/'| \
+  tr -d '[:space:]' \
 );
 echo $nvme_link;