TipsOnPX

Tips

Delete the pods forcely:

// kubectl >= 1.5
# kubectl delete pods <pod> --grace-period=0 --force
// kubectl < 1.4
# kubectl delete pods <pod> --grace-period=0 

Install jq(Command-line JSON processor) :

wget -O jq https://github.com/stedolan/jq/releases/download/jq-1.5/jq-linux64
chmod +x ./jq
cp jq /usr/bin

px volume operation:

# pxctl v l
# pxctl v d XXXXXXX

Before you run px on k8s(offline), you have to manually install following packages:

# yum install -y linux-headers linux-devel gcc

kubectl get pods failure:

Change the hostname from: like k8sMaster->k8smaster

Mark node as unschedulable/schedulable.

kubectl cordon NODE
kubectl uncordon NODE

Delete pod issue:

# journalctl -lfu kubelet
# lsattr /var/lib/kubelet/pods/2176d3a8-984f-11e7-98c4-5254004b207b/volumes/kubernetes.io~portworx-volume
# chattr -i /var/lib/kubelet/pods/2176d3a8-984f-11e7-98c4-5254004b207b/volumes/kubernetes.io~portworx-volume/pvc-21522191-984f-11e7-98c4-5254004b207b

BuildDebianDockerImageLocally

AIM

Recently I am working in a network isolated environment, this means, I am unable to connect to internet freely. But I have to finish my working using some specific docker images, how? So I have to build them locally using iso.

Preparation

Download debian dvds from internet and tranfer them into the intranet:

# ls -l debian*
-rw-r--r-- 1 dash root 3.6G Jul 21 00:59 debian-9.0.0-amd64-DVD-1.iso
-rw-r--r-- 1 dash root 4.4G Jul 21 01:57 debian-9.0.0-amd64-DVD-2.iso
-rw-r--r-- 1 dash root 4.4G Jul 21 02:52 debian-9.0.0-amd64-DVD-3.iso

Install debian in virtualbox using debian-9.0.0-amd64 DVD1 iso. Using basic desktop with sshd server.

Repository

Change the repository with following command:

# mount -t iso9660 -o loop /media/sdb/iso/debian-9.0.0-amd64-DVD-1.iso /media/sdb/debianrepo/cd1/
# mount -t iso9660 -o loop /media/sdb/iso/debian-9.0.0-amd64-DVD-2.iso /media/sdb/debianrepo/cd2/
# mount -t iso9660 -o loop /media/sdb/iso/debian-9.0.0-amd64-DVD-3.iso /media/sdb/debianrepo/cd3/

While the directory /media/sdb/debianrepo/ is the directory under the web server. Thus we could change the apt’s source file pointint to this webserver.

# vim /etc/apt/sources.list
deb http://192.168.56.1/debianrepo/cd1/	stable main contrib
deb http://192.168.56.1/debianrepo/cd2/	stable main contrib
deb http://192.168.56.1/debianrepo/cd3/	stable main contrib

Enable the Unauthenticated installation, and install vim for testing:

# vim /etc/apt/apt.conf.d/99myown 
APT::Get::AllowUnauthenticated "true";
# apt-get update
# apt-get -y install vim

BootStrap

Standard Bootstrap won’t be used, so we have to use a tool called demoostrap.
Download position:

# git clone https://github.com/jwilk/demoostrap.git

Install some necessray packages:

# apt-get install -y python3-debian apt-utils debootstrap dpkg-repack

demoostrap the basic filesystem via:

# mkdir docker_root
# ./demoostrap docker_root/
# du -hs docker_root/
179M	docker_root/

In next step we will chroot into this new filesystem and install some necessary package.

chroot

The filesystem under docker_root only contains basic filesystem. In order to work properly we have to install at least minimum apt-get, so following are the steps:

# mount -t devpts devpts docker_root/dev/pts
# mount -t proc proc docker_root/proc
# mount -t sysfs sysfs docker_root/sys

Before chroot into the system we have to download some packages manually into the docker_root folder, because in chrooted system we could only use dpkg for installation.

# mkdir -p docker_root/install
# cd docker_root/install
# wget http://192.192.192.91/debianrepo/cd1/debian/debian/pool/main/a/apt/apt_1.4.6_amd64.deb
# wget http://192.192.192.91/debianrepo/cd1/debian/pool/main/a/apt/libapt-pkg5.0_1.4.6_amd64.deb
# wget http://192.192.192.91/debianrepo/cd1/debian//pool/main/g/gcc-6/libstdc++6_6.3.0-18_amd64.deb
# wget http://192.192.192.91/debianrepo/cd1/debian/pool/main/a/adduser/adduser_3.115_all.deb
# wget http://192.192.192.91/debianrepo/cd1/debian/pool/main/d/debian-archive-keyring/debian-archive-keyring_2017.5_all.deb
# wget http://192.192.192.91/debianrepo/cd1/debian//pool/main/g/gnupg2/gpgv_2.1.18-6_amd64.deb

Now chroot in, and manually install these packages:

# chroot docker_root/
#  cd /install
# dpkg -i gpgv_2.1.18-6_amd64.deb 
# dpkg -i libstdc++6_6.3.0-18_amd64.deb 
# dpkg -i libapt-pkg5.0_1.4.6_amd64.deb 
# dpkg -i debian-archive-keyring_2017.5_all.deb 
# dpkg -i adduser_3.115_all.deb 
# dpkg -i apt_1.4.6_amd64.deb
# which apt-get
/usr/bin/apt-get

Further Modification

In host machine, we manually change the sources.list file and Now we could exit the chroot system, and tar docker_root directory,

# vim etc/apt/sources.list
deb http://192.168.56.1/debianrepo/cd1/	stable main contrib
deb http://192.168.56.1/debianrepo/cd2/	stable main contrib
deb http://192.168.56.1/debianrepo/cd3/	stable main contrib

Enable the Unauthenticated installation:

# vim etc/apt/apt.conf.d/99myown 
APT::Get::AllowUnauthenticated "true";

zip and import

tar the directory using following command:

# tar czvf docker_root.tar.gz docker_root/

Then in the untared directory you could import it into docker repository via:

# tar -c * | docker import - myowndebian:raw
# docker images | grep myowndebian
myowndebian                                                    raw                 909759ad7fad        23 seconds ago      189MB
# docker run -it myowndebian:raw /bin/bash
root@f95e7f8d6427:/# ls
bin   dev  home     lib    media  opt	root  sbin  sys  usr
boot  etc  install  lib64  mnt	  proc	run   srv   tmp  var

At this point, you have a selt-built docker box, from this start point you could add more packages into your docker images and form your own images offline. Just enjoy it!

SetupVinoServer

Background

For enable rdp server, but I installed vino server for vncserver, faint.

CentOS Configuration

Install Gnome Desktop.

Enable root autologin(This is pretty dangerous):

# vim /etc/gdm/custom.conf 

[daemon]
AutomaticLoginEnable=true
AutomaticLogin=username

So next time you will login to the desktop automatically.

Vino Server

Vino will be automatically installed for gnome desktop ,config it via:

# gsetting set org.gnome.Vino require-encryption false

Also setting up the password.

Now reboot the machine you could enjoy the vncserver.

xrdp

Install xrdp via epel:

# yum install -y xrdp
# systemctl enable xrdp.service
# systemctl start xrdp.service
# echo "mate-session" > ~/.Xclients
# chmod +x ~/.Xclients
# sudo systemctl restart xrdp.service

Then using some rdp clients for connecting to desktop.

Finding minimal packages

# /bin/bash
for i in `cat xrdp.txt`
do
	find_or_not=`find /media/sdb/centos73-isorepo/Packages/ | grep $i`
	if  [ $? == 1 ]
	then
		echo $i
	fi
done

OnAirDetection

Direct Read From Serial Port

Arduino mega2560 Code:

void setup() {
  pinMode(0,INPUT_PULLUP); 
  pinMode(1,INPUT_PULLUP); 
}

void loop() {
}

This code will turn mega2560 into a USB-TTL transmitter, thus you could directly read from the serial port and display them in hex mode:

# cat /dev/ttyACM0 | xxd -p -c 9
ffff01270005020534
ffff01270005020534
ffff01270005020534
ffff01270005020534
....

According to the reference manual,

we know the air is 0.05 mg/m3.

Read From Arduino Mega2560

Code:

void setup() {
  // initialize both serial ports:
  Serial.begin(9600);
  Serial2.begin(9600,SERIAL_8N1);

    while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }


    while (!Serial2) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  // prints title with ending line break
  Serial.println("ASCII Table ~ Character Map");
}

void loop() {


   for (int i=0; i<9; i++) {

    while(!Serial2.available()); // wait for a character
    int incomingByte = Serial2.read();
    Serial.print(incomingByte,HEX);
    Serial.print(' ');

   }
   Serial.println();
}

Result:

Problem

How to detect the result? Start from FF FF?

Should be

Fixed-Bug

Every time it will print starting with FF FF:

int incomingByte=0;
int vanishByte=0;

void setup() {
  // initialize both serial ports:
  Serial.begin(9600);
  Serial2.begin(9600,SERIAL_8N1);

    while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }


    while (!Serial2) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  // prints title with ending line break
  Serial.println("ASCII Table ~ Character Map");
}

void loop() {

    //Serial.println();
   //for (int i=0; i<9; i++) {
    while(!Serial2.available()); // wait for a character
    vanishByte = incomingByte;
    incomingByte = Serial2.read();
    if((incomingByte == 0xFF) && (vanishByte != 0xFF))
    {
      Serial.println();
    }
    Serial.print(incomingByte,HEX);
    Serial.print(' ');
   //}
   //Serial.println();
}

OnFIOTesting

Environment

bare metal vs kvm vs docker Testing script:

#!/bin/bash
function tgt_r {
fio -filename=/root/ioscript/ccc -direct=1 -iodepth 4 -thread -rw=read -ioengine=libaio -bs=$1 -size=120G  -runtime=200 -group_reporting -name=mytest &>> s_r_test
}

function tgt_w {
fio -filename=/root/ioscript/ccc -direct=1 -iodepth 4 -thread -rw=write -ioengine=libaio -bs=$1 -size=120G  -runtime=200 -group_reporting -name=mytest &>> s_w_test
}


function tgt_rr {
fio -filename=/root/ioscript/ccc -direct=1 -iodepth 4 -thread -rw=randread -ioengine=libaio -bs=$1 -size=120G  -runtime=200 -group_reporting -name=mytest &>> r_r_test
}

function tgt_rw {
fio -filename=/root/ioscript/ccc -direct=1 -iodepth 4 -thread -rw=randwrite -ioengine=libaio -bs=$1 -size=120G  -runtime=200 -group_reporting -name=mytest &>> r_w_test
}

mkdir -p /root/ioscript
rm -f /root/ioscript/ccc; touch /root/ioscript/ccc
tgt_r 128K
rm -f /root/ioscript/ccc; touch /root/ioscript/ccc
tgt_w 128K
rm -f /root/ioscript/ccc; touch /root/ioscript/ccc
tgt_rr 4K
rm -f /root/ioscript/ccc; touch /root/ioscript/ccc
tgt_rw 4K

Sequence read/write, 128K. Random read/write: 4K.

KVM using block device:

Result:

Bare Metal:

Sequence Read: 1000
Sequence Write: 893
Random Read: 1000
Random Write: 131 

KVM:

Sequence Read: 800
Sequence Write: 795
Random Read: 84
Random Write: 107

Docker:

Sequence Read: 975
Sequence Write: 909
Random Read: 114
Random Write: 81

Seems Not OK…….

Will use another disk for testing.