zedhook is a script that can act as the "mail" program for the ZFS Event Daemon or ZED.
Instead of sending an email when ZFS encounters an error, zedhook will POST JSON like this:
{
"subject": "ZFS checksum error for backup on zedhost",
"message": "ZFS has detected a checksum error: eid: 5788 class: checksum host: zedhost time: 2016-06-12 20:48:03-0500 vtype: disk vpath: /dev/sdd1 vguid: 0x1A7CE1031E023015 cksum: 2472 read: 0 write: 0 pool: backup"
}
Using the wget command (you must have wget installed):
wget -O- --header=Content-Type:application/json --post-data=...
To whatever endpoint you specify in ZED's /etc/zfs/zed.d/zed.rc like this:
##
# zed.rc
#
# This file should be owned by root and permissioned 0600.
##
##
# Email address of the zpool administrator for receipt of notifications;
# multiple addresses can be specified if they are delimited by whitespace.
# Email will only be sent if ZED_EMAIL_ADDR is defined.
# Disabled by default; uncomment to enable.
#
ZED_EMAIL_ADDR="zed@hook.com"
##
# Name or path of executable responsible for sending notifications via email;
# the mail program must be capable of reading a message body from stdin.
# Email will only be sent if ZED_EMAIL_ADDR is defined.
#
ZED_EMAIL_PROG="/usr/local/bin/zedhook"
##
# Command-line options for ZED_EMAIL_PROG.
# The string @ADDRESS@ will be replaced with the recipient email address(es).
# The string @SUBJECT@ will be replaced with the notification subject;
# this should be protected with quotes to prevent word-splitting.
# Email will only be sent if ZED_EMAIL_ADDR is defined.
#
ZED_EMAIL_OPTS="-s '@SUBJECT@' https://zapier.com/hooks/catch/<snip>/<snip>/"
##
# Minimum number of seconds between notifications for a similar event.
#
ZED_NOTIFY_INTERVAL_SECS=3600
You'll notice that I've set the ZED_EMAIL_ADDR to a dummy value so ZED will run ZED_EMAIL_PROG.
I've set the ZED_EMAIL_PROG to /usr/local/bin/zedhook, which means I've downloaded the zedhook script to /usr/local/bin/. You can put the zedhook script anywhere on your system, as long as you tell ZED about the location by setting ZED_EMAIL_PROG accordingly.
Finally, ZED_EMAIL_OPTS has had the address part set to a Zapier webhook, but you can have yours POST to any endpoint ready to consume the JSON.
Additionally, zedhook will log all messages to your server local log directory at /var/log/zedhook.log.
If there are problems reported by ZED, the contents of that log file will contain entries that look like this:
|-------------------------- 2016-06-13 03:02:50 UTC --------------------------|
Subject: ZFS checksum error for backup on zedhost
ZFS has detected a checksum error:
eid: 5788
class: checksum
host: zedhost
time: 2016-06-12 20:48:03-0500
vtype: disk
vpath: /dev/sdd1
vguid: 0x1A7CE1031E023015
cksum: 2472
read: 0
write: 0
pool: backup
|-----------------------------------------------------------------------------|
This is the exact same information sent by POST as JSON to your endpoint, but all in one conveinent place, which is especially useful if the endpoint was down.
zedhook emulates the API of the linux mail program (to the limited extent that was needed for ZED).
It can accept arguments like:
zedhook -s "Some kind of message" https://zapier.com/hooks/catch/<snip>/<snip>/ < somelogfile
So, perhaps it could be useful for replacing the mail program in other simple log programs.
Joel Kuzmarski
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