haridsv

What exactly is "iowait"?

To summarize it in one sentence, 'iowait' is the percentage
of time the CPU is idle AND there is at least one I/O
in progress.

Each CPU can be in one of four states: user, sys, idle, iowait.
Performance tools such as vmstat, iostat, sar, etc. print
out these four states as a percentage.  The sar tool can
print out the states on a per CPU basis (-P flag) but most

haridsv

javascript:s=document.createElement('script');s.type='text/javascript';document.body.appendChild(s);s.src='https://goo.gl/OrQlxL';void(0);

haridsv

NOTE: Doesn't work because of github CSP meta tags.

javascript:s=document.createElement('script');s.type='text/javascript';document.body.appendChild(s);s.src='https://git.io/JJTwA';void(0);

haridsv

document.getElementById("files_tab_counter").click();
setTimeout(function approvePR() {
    var ele = document.querySelector(".js-review-changes");
    if (! ele) {
        setTimeout(approvePR, 300);
        return;
    }
    ele.click();
    document.getElementById("pull_request_review_body").value = "LGTM";
    document.evaluate("//*/form/div[1]/fieldset/div/div[2]/span/label", document.querySelector("#review-changes-modal > div"), null, XPathResult.ANY_TYPE, null).iterateNext().click();

haridsv

import re

import click
from bs4 import BeautifulSoup


bookmarks = dict()
def add_bookmark(linknode, descnode):
    link = linknode.get("href")
    linktext = linknode.next.text.strip()

haridsv

#!/bin/bash

# Script for installing tmux on systems where you don't have root access.
# tmux will be installed in $HOME/local/bin.
# It's assumed that wget and a C/C++ compiler are installed.

# exit on error
set -e

# create our directories

haridsv

var currentUser = document.querySelector(".user-profile-link").href.replace(/.*\//, "")
document.querySelectorAll("div.js-comment.js-targetable-comment.js-updatable-content").forEach(function(n) {
    var authorNode = n.parentNode.querySelector(".author");
    if (authorNode && authorNode.textContent == currentUser) {
        n.parentNode.querySelectorAll(".js-toggle-outdated-comments").forEach(n => n.click());
    }
})

haridsv

One of the reasons that this failure occurs is because of the incorrect client setting of yarn.resourcemanager.cluster-id that ends up not matching the one in the cluster. This often results in a cryptic error that looks like this:

Failed to renew token: Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:test-local-EMPTY, Ident: (HDFS_DELEGATION_TOKEN token 40242 for hari)

Unfortunately, the original IOException seems to get completely lost, neither logged on the server nor gets seen on the client. When I put an extra trace log line to print the exception, I got this:

2016-06-06 12:57:57,394 ERROR [tionTokenRenewer #50] security.DelegationTokenRenewer - Failed to renew token: Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:test-local-EMPTY, Ident: (HDFS_DELEGATION_TOKEN token 40663 for sfdc)
java.io.IOException: Unable to map logical nameservice URI 'hdfs://test-local-EMPTY' to a NameNode. Local configuration does not have a failover proxy provider configured.
        at org.apache.hadoop.hdfs.DFSCl

haridsv

hbase(main):002:0> T = create 'emp',  {NAME => 'f', VERSIONS => 5}
0 row(s) in 1.1300 seconds

=> Hbase::Table - emp
hbase(main):003:0> T.put '001', 'f:name', 'Tom'
0 row(s) in 0.0890 seconds
hbase(main):003:0> T.put '001', 'f:name', 'Tom Too'
0 row(s) in 0.0890 seconds

haridsv

import sys
import cv

class FaceDetect():
    def __init__(self):
        cv.NamedWindow ("CamShiftDemo", 1)
        device = 0
        self.capture = cv.CaptureFromCAM(device)
        capture_size = (320,200)
        cv.SetCaptureProperty(self.capture, cv.CV_CAP_PROP_FRAME_WIDTH, capture_size[0])