hieuhtr / blog Goto Github PK

**Hieu Huynh**

Single-Core Score = 3973
Multi-Core Score = 7661

Single-Core Score = 2234
Multi-Core Score = 2099

Single-Core Score = 4043
Multi-Core Score = 3781

Single-Core Score = 3769 
Multi-Core Score = 3492

Single-Core Score = 1702
Multi-Core Score = 1594

Single-Core Score = 3039
Multi-Core Score = 2597

$ sudo snap install canonical-livepatch
error: cannot perform the following tasks:
- Setup snap "core" (1577) security profiles (cannot setup apparmor for snap "core": cannot load apparmor profile "snap.core.hook.configure": cannot load apparmor profile: exit status 1
apparmor_parser output:
Cache read/write disabled: interface file missing. (Kernel needs AppArmor 2.4 compatibility patch.)
Warning: unable to find a suitable fs in /proc/mounts, is it mounted?
Use --subdomainfs to override.
)
- Setup snap "core" (1577) security profiles (cannot load apparmor profile "snap.core.hook.configure": cannot load apparmor profile: exit status 1
apparmor_parser output:
Cache read/write disabled: interface file missing. (Kernel needs AppArmor 2.4 compatibility patch.)
Warning: unable to find a suitable fs in /proc/mounts, is it mounted?
Use --subdomainfs to override.
)

#Fetch kernel version
$ uname -a
Linux snode 4.9.15-x86_64-linode81 #1 SMP Fri Mar 17 09:47:36 EDT 2017 x86_64 x86_64 x86_64 GNU/Linux

#Find it
$ sudo find / -name "4.9.15-x86_64-linode81"
/lib/modules/4.9.15-x86_64-linode81

#List all Linode's kernel
lib/modules$ ls -lh
total 24K
drwxr-xr-x 5 root root 4.0K Sep  9  2016 4.4.0-36-generic
drwxr-xr-x 2 root root 4.0K Sep  9  2016 4.6.5-x86_64-linode71
drwxr-xr-x 2 root root 4.0K Sep 15  2016 4.7.0-x86_64-linode72
drwxr-xr-x 2 root root 4.0K Apr 13 14:40 4.9.15-x86_64-linode81
drwxr-xr-x 2 root root 4.0K Apr  1 12:35 4.9.7-x86_64-linode80
drwxr-xr-x 2 root root 4.0K Sep  9  2016 grub-2.00-17-linode.img

# config to don't allow the browser to render the page inside a frame or iframe
# and avoid clickjacking http://en.wikipedia.org/wiki/Clickjacking
# if you need to allow [i]frames, you can use SAMEORIGIN or even set a URI with ALLOW-FROM URI
# https://developer.mozilla.org/en-US/docs/HTTP/X-Frame-Options

add_header X-Frame-Options SAMEORIGIN;
# when serving user-supplied content, include a X-Content-Type-Options: nosniff header along with the Content-Type: header,
# to disable content-type sniffing on some browsers.
# https://www.owasp.org/index.php/List_of_useful_HTTP_headers
# currently suppoorted in IE > 8 http://blogs.msdn.com/b/ie/archive/2008/09/02/ie8-security-part-vi-beta-2-update.aspx
# http://msdn.microsoft.com/en-us/library/ie/gg622941(v=vs.85).aspx
# 'soon' on Firefox https://bugzilla.mozilla.org/show_bug.cgi?id=471020

add_header X-Content-Type-Options nosniff;
# This header enables the Cross-site scripting (XSS) filter built into most recent web browsers.
# It's usually enabled by default anyway, so the role of this header is to re-enable the filter for 
# this particular website if it was disabled by the user.
# https://www.owasp.org/index.php/List_of_useful_HTTP_headers

add_header X-XSS-Protection "1; mode=block";
mysql> FLUSH TABLES WITH READ LOCK;
shell> mysql -u root -p abc_prod
mysql> SET GLOBAL slow_query_log = 'ON';
mysql> SHOW VARIABLES LIKE 'slow_query_log_file';
+---------------------+-----------------------------+
| Variable_name       | Value                       |
+---------------------+-----------------------------+
| slow_query_log_file | /var/lib/mysql/db3-slow.log |
+---------------------+-----------------------------+
1 row in set (0.00 sec)
mysql> SET GLOBAL long_query_time = 5;
mysql> SELECT SLEEP(10);
root@db3:/home/ubuntu:~$ cat /var/lib/mysql/db3-slow.log

/usr/sbin/mysqld, Version: 5.6.35-log (MySQL Community Server (GPL)). started with:
Tcp port: 3306  Unix socket: /var/run/mysqld/mysqld.sock
Time                 Id Command    Argument
# Time: 170321  7:15:52
# User@Host: root[root] @ localhost []  Id:  1160
# Query_time: 7.000249  Lock_time: 0.000000 Rows_sent: 1  Rows_examined: 0
SET timestamp=1490080552;
SELECT SLEEP(7);
# Time: 170321  7:17:31
# User@Host: root[root] @ localhost []  Id:  1161
# Query_time: 10.000215  Lock_time: 0.000000 Rows_sent: 1  Rows_examined: 0
use abc_prod;
SET timestamp=1490080651;
SELECT SLEEP(10);
root@db3:/home/ubuntu:~$ mysqldumpslow /var/lib/mysql/db3-slow.log
Reading mysql slow query log from /var/lib/mysql/db3-slow.log
Count: 2  Time=8.50s (17s)  Lock=0.00s (0s)  Rows=1.0 (2), root[root]@localhost
  SELECT SLEEP(N)
mysql> SET GLOBAL slow_query_log = 'OFF';
❯❯ echo "Packet data right here" > /dev/udp/172.30.31.32/1514

❯❯ tcpdump -nei eth0 udp port 1514

tailf [option] <file>
Follow the growth of a log file.
Options:
 -n, --lines <number>   output the last <number> lines
 -<number>              same as '-n <number>'

 -h, --help     display this help and exit
 -V, --version  output version information and exit
For more details see tailf(1).
Warning: use of 'tailf' is deprecated, use 'tail -f' instead.
$ watch -n 1 tail test.log
-----
Every 1.0s: tail test.log

</script>

  </body>

</html>
hello-test color
color again

$ devops@snode:/proc$ watch -n 1 head meminfo
Every 1.0s: head meminfo

MemTotal:        1012720 kB
MemFree:          415876 kB
MemAvailable:     847124 kB
Buffers:           29064 kB
Cached:           445560 kB
SwapCached:            0 kB
Active:           237192 kB
Inactive:         259380 kB
Active(anon):      26888 kB
Inactive(anon):    47504 kB

# clean buffer and cached
root@appv2-1:~# free -m && sync && echo 3 > /proc/sys/vm/drop_caches && free -m

# step by step
root@appv2-1:~# free -m
             total       used       free     shared    buffers     cached
Mem:          3951       3260        691          0         46        121
-/+ buffers/cache:       3092        859
Swap:         4095          0       4095
root@appv2-1:~# sync
root@appv2-1:~# echo 3 > /proc/sys/vm/drop_caches
root@appv2-1:~# free -m
             total       used       free     shared    buffers     cached
Mem:          3951       3065        886          0          2         22
-/+ buffers/cache:       3040        911
Swap:         4095          0       4095

❯❯ brew install awscli
Warning: awscli-1.11.65 already installed, it's just not linked.
❯❯ brew link awscli
Linking /usr/local/Cellar/awscli/1.11.65... 8 symlinks created
❯❯ aws --version
aws-cli/1.11.65 Python/2.7.10 Darwin/16.4.0 botocore/1.5.28

#!/bin/bash
/usr/bin/osascript -e 'display notification "Ngồi thẳng lưng + uống nước" with title "Suggestion"'
❯❯ sudo chmod +x /Users/admin/Documents/MacNotification.sh
❯❯ /Users/admin/Documents/MacNotification.sh
❯❯ crontab -e

# Paste this line to crontab's configuration
10 * * * *  /Users/admin/Documents/MacNotification.sh
#!/usr/bin/env python2
print '3 / 2 =', 3 / 2
print '3 // 2 =', 3 // 2
print '3 / 2.0 =', 3 / 2.0
print '3 // 2.0 =', 3 // 2.0
❯❯ python 2.py
3 / 2 = 1
3 // 2 = 1
3 / 2.0 = 1.5
3 // 2.0 = 1.0

#!/usr/bin/env python3
print('3 / 2 =', 3 / 2)
print('3 // 2 =', 3 // 2)
print('3 / 2.0 =', 3 / 2.0)
print('3 // 2.0 =', 3 // 2.0)
❯❯ python3 3.py
3 / 2 = 1.5
3 // 2 = 1
3 / 2.0 = 1.5
3 // 2.0 = 1.0
mysql> SHOW variables like `net_read_timeout` 
mysql> SET GLOBAL `net_read_timeout` = 360;
tar -xzf foo.tar.gz
gunzip -c foo.tar.gz | tar xopf -
tar xopf foo.tar

unzip -a foo.zip

unrar x foo.rar

Supported escape sequences:
  ~.  - terminate session
  ~B  - send a BREAK to the remote system
  ~R  - Request rekey (SSH protocol 2 only)
  ~#  - list forwarded connections
  ~?  - this message
  ~~  - send the escape character by typing it twice
(Note that escapes are only recognized immediately after newline.)

# Setup replication master slave
# On Master
bind-address       = 172.30.20.111
event-scheduler  = on
server-id              = 1

log-bin
binlog-format      = row
binlog-do-db       = xxx_production
binlog-ignore-db = mysql
binlog-ignore-db = test
log_bin                  = /var/log/mysql/mysql-bin.log

sync_binlog          = 0
expire_logs_days = 2
# End of master config

# Setup replication master slave
# On Slave
bind-address       = 172.30.20.222
event_scheduler  = off
server-id              = 2

log-bin
binlog-format      = row
binlog-do-db       = xxx_production
binlog-ignore-db = mysql
binlog-ignore-db = test
log_bin                  = /var/log/mysql/mysql-bin.log

sync_binlog           = 0
expire_logs_days  = 2
# End of slave config

GRANT REPLICATION SLAVE ON *.* TO 'slave_user'@'172.30.20.222' IDENTIFIED BY 'sl@ve';
FLUSH PRIVILEGES;

FLUSH TABLES WITH READ LOCK;
SHOW MASTER STATUS;

+----------------+----------+--------------+------------------+
| File           | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+----------------+----------+--------------+------------------+
| m01-bin.000001 |      827 | xxx_prod     | mysql,test       |
+----------------+----------+--------------+------------------+

$ mysqldump -u root -p --all-databases > xxx_production.sql

mysql> CREATE DATABASE IF NOT EXISTS xxx_production;
mysql> USE xxx_production;
mysql> source dump.sql

CHANGE MASTER TO MASTER_HOST='172.30.20.111', MASTER_USER='slave_user', MASTER_PASSWORD='sl@ve', MASTER_LOG_FILE='mysql-bin.000005', MASTER_LOG_POS=80;
START SLAVE
SHOW SLAVE STATUS\G

+ SHOW GLOBAL VARIABLES LIKE 'binlog_format';
+ SET GLOBAL binlog_format = 'ROW';

sudo apt-get install mailutils
sudo apt-get install heirloom-mailx

ubuntu@db3:~$ mail -s "Test email from database server" [email protected]
Hi,

Hello world.

Best,EOT
#/etc/security/limits.conf

elasticsearch - nofile 65535
elasticsearch - memlock unlimited

sudo -u elasticsearch -s "ulimit -Sn"

cluster.name: myFirstElasticsearchCluster
node.name: $hostname

index.number_of_shards: 4 x $numberOfNodes
index.number_of_replicas: 0  # See explanation below
bootstrap.mlockall: true

path.data: /data/elasticsearch # Additional directories can be added here, comma-delimited.
                               # Data will be striped across the directories

http.max_content_length: 256mb
# Run Elasticsearch as this user ID and group ID
#ES_USER=elasticsearch
#ES_GROUP=elasticsearch

# Heap Size (defaults to 256m min, 1g max)
ES_HEAP_SIZE=1500m

# Heap new generation
#ES_HEAP_NEWSIZE=

# max direct memory
#ES_DIRECT_SIZE=

# Maximum number of open files, defaults to 65535.
#MAX_OPEN_FILES=65535

# Maximum locked memory size. Set to "unlimited" if you use the
# bootstrap.mlockall option in elasticsearch.yml. You must also set
# ES_HEAP_SIZE.
MAX_LOCKED_MEMORY=unlimited

# Maximum number of VMA (Virtual Memory Areas) a process can own
#MAX_MAP_COUNT=262144

# Elasticsearch log directory
#LOG_DIR=/var/log/elasticsearch

# Elasticsearch data directory
#DATA_DIR=/var/lib/elasticsearch

# Elasticsearch work directory
#WORK_DIR=/tmp/elasticsearch

# Elasticsearch configuration directory
#CONF_DIR=/etc/elasticsearch

# Elasticsearch configuration file (elasticsearch.yml)
#CONF_FILE=/etc/elasticsearch/elasticsearch.yml

# Additional Java OPTS
#ES_JAVA_OPTS=

# Configure restart on package upgrade (true, every other setting will lead to not restarting)
#RESTART_ON_UPGRADE=true
git checkout master

git log

commit b4fcbeb56694aXXXXXXXXXXXXXX
Merge: 4dfb327 141fcb8

  1 Revert "Merged in SS-2141-Redis-cache-Change-connection-of-Redis-on-stage (pull request #148)"
Author: Hieu Huynh <[email protected]>
Date:   Mon Mar 6 09:52:57 2017 +0000

    Merged in SS-2141-Redis-cache-Change-connection-of-Redis-on-stage (pull request #148)

    SS-2141 Redis cache - Change connection of Redis on stage

    Approved-by: Hieu Huynh
    Approved-by: XXXX
    Approved-by: XXXX

commit 141fcb88781b0d65addXXXXXXXXXXXXXXX
Author: Hieu Huynh <[email protected]>
Date:   Mon Mar 6 14:59:29 2017 +0700

    Change connection between webapp and redis service from service inside app1.stage to new Redis instance

commit 4dfb3276bacc2986dc513XXXXXXXXXXXX
Merge: 21f6edf c2f1XXX
Author: Hieu Huynh <[email protected]>
Date:   Tue Jan 17 21:51:35 2017 +0700

    Merged in SS-1801-Rotate-key-access-to-bastion-server (pull request #147)

    SS-1801-Rotate-key-access-to-bastion-server
commit b4fcbeb56694aXXXXXXXXXXXXXX
Merge: 4dfb327 141fcb8

git revert -m 1 <commit-hash> 
git commit -m "Reverting the last commit which messed the repo."
git push -u origin master

// Place your settings in this file to overwrite the default settings
{
    "editor.fontSize": 12,
    "window.reopenFolders": "all",
    "editor.fontFamily": "Menlo, Monaco, 'Courier New', monospace",
    "editor.quickSuggestions": true,
    "editor.quickSuggestionsDelay": 0,
    "editor.renderWhitespace": "all",
    "workbench.sideBar.location": "left",
    "workbench.statusBar.visible": true,
    "files.associations": {
        "*.cnf": "shellscript",
        "*.md": "markdown",
        "*.markdown": "markdown"
    },
    "files.hotExit": "onExit",
    "window.titleBarStyle": "native",
    "window.zoomLevel": 0,
    "vsicons.dontShowNewVersionMessage": true,
    "workbench.editor.tabCloseButton":"right",
    "extensions.autoUpdate": true,
    "terminal.integrated.scrollback": 2000,
    "clock.dateFormat": "hh:MM TT - dddd mmm d",
    "workbench.iconTheme": "vscode-icons",
    "workbench.colorTheme": "Gruvbox Dark (Medium Contrast)",
    "editor.cursorStyle": "block",
    "terminal.integrated.cursorStyle": "block",
    "editor.cursorBlinking": "solid"
}
mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State:
                  Master_Host: 172.31.24.216
                  Master_User: slave_user
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: util11-bin.000025
          Read_Master_Log_Pos: 366468954
               Relay_Log_File: mysqld-relay-bin.000003
                Relay_Log_Pos: 4
        Relay_Master_Log_File: util11-bin.000025
             Slave_IO_Running: No
            Slave_SQL_Running: Yes

### etherconf DEBCONF AREA. DO NOT EDIT THIS AREA OR INSERT TEXT BEFORE IT.
127.0.0.1 localhost ::1 localhost
ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts
192.168.0.99 debian.localdomain.com debian
### END OF DEBCONF AREA. PLACE YOUR EDITS BELOW; THEY WILL BE PRESERVED.
192.168.0.1 ws001

{
 } &> /path/to/log/file

❯❯ ./yourscript.sh > output.txt

❯❯ cat MacNotification.sh
#!/bin/bash
{
echo "Test output"
/usr/bin/osascript -e 'display notification "Ngồi thẳng lưng + uống nước" with title "Suggestion"'
} &> /Users/admin/Documents/Tools/output.log

Provider	vCPU	Single-Core	Multi-Core	Details
Macbook	4	3973	7661	https://browser.geekbench.com/v4/cpu/2431825
Linode	1	2234	2099	https://browser.geekbench.com/v4/cpu/2436485
OVH	1	4043	3781	https://browser.geekbench.com/v4/cpu/8802946
Scaleway	1	1702	1594	https://browser.geekbench.com/v4/cpu/11047834
GCP	1	3039	2597	https://browser.geekbench.com/v4/cpu/11463325
hetzner	1	2340	2181	https://browser.geekbench.com/v4/cpu/14235288

hieuhtr / blog Goto Github PK

blog's Introduction

Highlights articles from my personal blog blog.tracelog.in

Presentations

blog's People

Contributors

Stargazers

Watchers

Forkers

blog's Issues

Benchmarked by geekbench_x86_64

On my Mac:

On Linode server

On OVH vm 2.5$/month

On Scaleway vm 2.27$/month

On GCP vm f1-micro 6.$/month (but free tier)

... To be continue

Question:

Answer:

More fun:

Problem?

Investigate

Tại sao họ lại custom?

Vậy kernel này được store ở đâu?

Application Load Balancer

Benefits - Compare with Classic Load Balancer

Listeners for Elastic Load Balancer AWS

ELB's terms:

X-Frame-Options

X-Content-Type-Options

X-XSS-Protection

Reference:

Free command

Problem & Question

Research & Answer

Must learn:

What is FLUSH TABLES WITH READ LOCK in MySQL?

Important:

Issue & investigating:

Hotfix and prevent?

Write up about this vulnerability

❓ What is slow query log?

🔥 How to enable?

How to turn it off?

Problem:

Solution:

Problem:

Solution:

More fun:

What's Launch More Like This ?

Most important thing

How ?

When you found this error of mysqldump

How to fix?

Note

Error

How to fix?

Reference:

Một kiểu nhìn về dữ liệu

Issue

Solution

Reference:

Python2

Python3

Issue:

Root cause:

Solution:

Think more

Reference:

What is a CNAME record?

Example

Using Terminal command-line to unpack archived files

For your information:

Lessons learned:

Problem:

Solved: Press ~ then press .

Replication Master-Slave Configurations

Create Configurations On Master Database /etc/mysql/my.cnf

Create Configurations On Slave Database /etc/mysql/my.cnf

Create user for Replication

Benchmarked by `geekbench_x86_64`

Solved: Press `~` then press `.`