Various Kubernetes / Google Container Engine tools

kube-resources.py

#!/usr/bin/env python

##
# kube-resources.py
# Collate and report Kubernetes pod usages vs. node limits.
#
# Assumes `kubectl` is installed and available.
#
# Author: Henry Cooke, me@prehensile.co.uk
# Version: 20150816
# 

import json
import subprocess
import re
import math


def main():
    
    # get pod & node data
    pod_dict = get_pods()
    node_dict = get_nodes()

    # step through nodes hash
    for node_name in node_dict:

        # print node info
        print "---\nNODE:\t%s\n---" % node_name
        node = node_dict[node_name]
        stat = node.get("status")
        cap = stat.get("capacity")
        cpu_capacity = 0
        mem_capacity = 0
        if cap:
            cpu_capacity = parse_cpu( cap.get("cpu") )
            mem_capacity = parse_mem( cap.get("memory") )

        # print pods
        pods = pod_dict.get( node_name )
        if (pods is not None) and (len(pods)>0):
            total_cpu, total_mem, rows = parse_pods( pods )
            print_pods( rows )
            print "---"                    
            print "Memory allocated: %s (%2.2f%% of capacity)" % (
                format_mem(total_mem,"Mi"),
                (float(total_mem)/float(mem_capacity))*100.0
            )
            print "CPU allocated: %s (%2.2f%% of capacity)" % (
                format_cpu(total_cpu,"m"),
                (total_cpu/cpu_capacity)*100.0
            )

        # print node capacity
        print "---"                    
        print "Memory capacity: %s" % format_mem(mem_capacity,"Mi")
        print "CPU capacity: %s" % format_cpu(cpu_capacity,"m")
        print "---\n"

def get_nodes():
    node_dict = {}
    node_json = json.loads(
        subprocess.check_output(
            [ "kubectl", "get", "nodes", "-o", "json" ]
        )
    )
    node_dict = {}
    for node in node_json["items"]:
        node_dict[ node["metadata"]["name"] ] = node
    return node_dict

def get_pods():
    pod_json = json.loads(
        subprocess.check_output(
            [ "kubectl", "get", "pods", "-o", "json", "--all-namespaces" ]
        )
    )
    pod_dict = {}
    for pod in pod_json["items"]:
        spec = pod["spec"]
        if "nodeName" in spec:
            node_name = spec["nodeName"]
            if node_name not in pod_dict:
                pod_dict[node_name] = []
            pod_dict[node_name].append(pod)
    return pod_dict

def parse_container( container ):
    container_name = container["name"]
    res = container.get("resources")
    cpu_limit = 0
    mem_limit = 0
    if res:
        limits = res.get("limits")
        if limits:
            cpu_limit = parse_cpu( limits.get("cpu") )
            mem_limit = parse_mem( limits.get("memory") )
    return container_name, cpu_limit, mem_limit

def print_pods( rows ):
    headers = [ "CONTAINER NAME", "NAMESPACE", "MEM LIMIT", "CPU LIMIT" ]
    # calculate inital column widths
    row_widths = [ len(col)+2 for col in headers ]
    # step through rows, find max widths for columns
    rows.insert( 0, headers )
    for row in rows:
        for i in range(len(row_widths)):
            row_widths[i] = max( row_widths[i], len("%s"%row[i])+2 )
    # generate format string, see https://docs.python.org/3/library/string.html#format-examples
    fmt = '{:<%d}{:<%d}{:<%d}{:<%d}' % tuple(row_widths)
    for row in rows: 
        print fmt.format(*row)

def parse_pods( pods ):
    total_cpu = 0
    total_mem = 0
    rows = []
    for pod in pods:
        spec = pod["spec"]
        m = pod["metadata"]
        namespace = m["namespace"]
        for container in spec["containers"]:
            container_name, cpu_limit, mem_limit = parse_container( container )
            total_cpu += cpu_limit
            total_mem += mem_limit
            rows.append( (container_name,namespace, format_mem(mem_limit,"Mi"), format_cpu(cpu_limit,"m")))
    rows.append( ["","","---","---"] )
    rows.append( ["","TOTALS",format_mem(total_mem,"Mi"),format_cpu(total_cpu,"m")] )
    return total_cpu, total_mem, rows

def parse_cpu( cpu ):
    """ Return CPU value in whole units """
    if cpu is None:
        return 0
    if type(cpu) is int:
        return cpu
    g = re.match('(\d*)(\w*)',cpu).groups()
    amt = int(g[0])
    if len(g) > 1:
        unit = g[1]
        # TODO: add more possible unit types?
        if unit == "m":
            amt = float(amt) / 1000.0
    return amt

def format_cpu( cpu, unit=None ):
    if unit.lower() == "m":
        # return CPU formatted in milliunits
        return "%0.0fm" % (float(cpu) * 1000.0)
    return cpu * 1000

def parse_mem( mem ):
    """ Return mem value in bytes """
    if mem is None:
        return 0
    if type(mem) is int:
        return mem
    g = re.match('(\d*)(\w*)',mem).groups()
    amt = int(g[0])
    if len(g) > 1:
        unit = g[1]
        # TODO: add more possible unit types?
        if unit.lower() == "ki":
            amt *= 1024
        elif unit.lower() == "mi":
            amt *= (1024 * 1024)
    return amt

def format_mem( mem, unit=None ):
    if unit.lower() == "ki":
        # return mem formatted in kibibytes
        return "%dKi" % (mem / 1024)
    elif unit.lower() == "mi":
        # return mem formatted in mebibytes
        return "%dMi" % (mem / math.pow(1024,2) )
    elif unit.lower() == "gi":
        # return mem formatted in gibibytes
        return "%dGi" % (mem / math.pow(1024,3) )
    return mem

# entrypoint...
if __name__ == '__main__':
    main()

rolling-update.sh

#!/usr/bin/env bash
for MODULE in "$@"
do
    kubectl rolling-update $MODULE --image=gcr.io/pastcards-1033/$MODULE
done