110 lines
3.9 KiB
Python
110 lines
3.9 KiB
Python
#!/usr/bin/env python3
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# zkpr.py - PVC Monitoring example plugin for Zookeeper
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# Part of the Parallel Virtual Cluster (PVC) system
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#
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# Copyright (C) 2018-2022 Joshua M. Boniface <joshua@boniface.me>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, version 3.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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#
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###############################################################################
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# This script provides an example of a PVC monitoring plugin script. It will create
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# a simple plugin to check the Zookeeper instance on the node for operation.
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# This script can thus be used as an example or reference implementation of a
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# PVC monitoring pluginscript and expanded upon as required.
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# A monitoring plugin script must implement the class "MonitoringPluginScript" which
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# extends "MonitoringPlugin", providing the 3 functions indicated. Detailed explanation
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# of the role of each function is provided in context of the example; see the other
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# examples for more potential uses.
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# WARNING:
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#
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# This script will run in the context of the node daemon keepalives as root.
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# DO NOT install untrusted, unvetted plugins under any circumstances.
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# This import is always required here, as MonitoringPlugin is used by the
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# MonitoringPluginScript class
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from pvcnoded.objects.MonitoringInstance import MonitoringPlugin
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# A monitoring plugin script must always expose its nice name, which must be identical to
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# the file name
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PLUGIN_NAME = "zkpr"
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# The MonitoringPluginScript class must be named as such, and extend MonitoringPlugin.
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class MonitoringPluginScript(MonitoringPlugin):
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def setup(self):
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"""
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setup(): Perform special setup steps during node daemon startup
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This step is optional and should be used sparingly.
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If you wish for the plugin to not zkpr in certain conditions, do any checks here
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and return a non-None failure message to indicate the error.
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"""
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pass
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def run(self, coordinator_state=None):
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"""
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run(): Perform the check actions and return a PluginResult object
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The {coordinator_state} can be used to check if this is a "primary" coordinator, "secondary" coordinator, or "client" (non-coordinator)
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"""
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# Run any imports first
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from kazoo.client import KazooClient, KazooState
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zk_conn = None
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# Set the health delta to 0 (no change)
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health_delta = 0
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# Craft a message that can be used by the clients
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message = "Successfully connected to Zookeeper on localhost"
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# Check the Zookeeper connection
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try:
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zk_conn = KazooClient(hosts=[f"{self.this_node.name}:2181"], timeout=1, read_only=True)
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zk_conn.start(timeout=1)
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data = zk_conn.get('/schema/version')
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except Exception as e:
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health_delta = 50
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message = f"Failed to connect to Zookeeper: {e}"
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finally:
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if zk_conn is not None:
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zk_conn.stop()
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zk_conn.close()
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# Set the health delta in our local PluginResult object
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self.plugin_result.set_health_delta(health_delta)
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# Set the message in our local PluginResult object
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self.plugin_result.set_message(message)
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# Return our local PluginResult object
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return self.plugin_result
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def cleanup(self):
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"""
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cleanup(): Perform special cleanup steps during node daemon termination
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This step is optional and should be used sparingly.
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"""
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pass
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