Add a new decision tree (not used for the moment)

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nicolargo 2021-03-21 18:29:56 +01:00
parent c96fee907e
commit 2d20e5967c

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@ -64,6 +64,101 @@ tree = [{'msg': 'No warning or critical alert detected',
'thresholds_min': 2},
]
# @TODO: change the algo to use the following decision tree
# Source: Inspire by https://scoutapm.com/blog/slow_server_flow_chart
# _yes means threshold >= 2
# _no means threshold < 2
# With threshold:
# - 0: OK
# - 1: CAREFUL
# - 2: WARNING
# - 3: CRITICAL
tree_new = {
'cpu_iowait': {
'_yes': {
'memswap': {
'_yes': {
'mem': {
'_yes': {
# Once you've identified the offenders, the resolution will again depend on whether their memory usage seems
# business-as-usual or not. For example, a memory leak can be satisfactorily addressed by a one-time or periodic
# restart of the process.
# - if memory usage seems anomalous: kill the offending processes.
# - if memory usage seems business-as-usual: add RAM to the server, or split high-memory using services to other servers.
'_msg': "Memory issue"
},
'_no': {
# ???
'_msg': "Swap issue"
}
}
},
'_no': {
# Low swap means you have a "real" IO wait problem. The next step is to see what's hogging your IO.
# iotop is an awesome tool for identifying io offenders. Two things to note:
# unless you've already installed iotop, it's probably not already on your system.
# Recommendation: install it before you need it - - it's no fun trying to install a troubleshooting
# tool on an overloaded machine (iotop requies a Linux of 2.62 or above)
'_msg': "I/O issue"
}
}
},
'_no': {
'cpu_total': {
'_yes': {
'cpu_user': {
'_yes': {
# We expect the usertime percentage to be high.
# There's most likely a program or service you've configured on you server that's hogging CPU.
# Checking the % user time just confirms this. When you see that the % usertime is high,
# it's time to see what executable is monopolizing the CPU
# Once you've confirmed that the % usertime is high, check the process list(also provided by top).
# Be default, top sorts the process list by % CPU, so you can just look at the top process or processes.
# If there's a single process hogging the CPU in a way that seems abnormal, it's an anomalous situation
# that a service restart can fix. If there are are multiple processes taking up CPU resources, or it
# there's one process that takes lots of resources while otherwise functioning normally, than your setup
# may just be underpowered. You'll need to upgrade your server(add more cores), or split services out onto
# other boxes. In either case, you have a resolution:
# - if situation seems anomalous: kill the offending processes.
# - if situation seems typical given history: upgrade server or add more servers.
'_msg': "CPU issue with user process(es)"
},
'_no': {
'cpu_steal': {
'_yes': {
'_msg': "CPU issue with stolen time. System running the hypervisor may be too busy."
},
'_no': {
'_msg': "CPU issue with system process(es)"
}
}
}
}
},
'_no': {
'_yes': {
# ???
'_msg': "Memory issue"
},
'_no': {
# Your slowness isn't due to CPU or IO problems, so it's likely an application-specific issue.
# It's also possible that the slowness is being caused by another server in your cluster, or
# by an external service you rely on.
# start by checking important applications for uncharacteristic slowness(the DB is a good place to start),
# think through which parts of your infrastructure could be slowed down externally. For example, do you
# use an externally hosted email service that could slow down critical parts of your application?
# If you suspect another server in your cluster, strace and lsof can provide information on what the
# process is doing or waiting on. Strace will show you which file descriptors are being read or written
# to(or being attempted to be read from) and lsof can give you a mapping of those file descriptors to
# network connections.
'_msg': "External issue"
}
}
}
}
}
}
def global_message():
"""Parse the decision tree and return the message.