Let’s briefly look back on last year!


Background

I write this retrospective because I wrote it every year and there were some things that I’d like to write. Here are past retrospectives.

It took more than 3 days to write [Retrospective](EN) Retrospective of a tenth-year major in computer science and engineering post. It was a long post because it was to commemorate my 30 years old. However this time I’m going to write a retrospective of my job, major, and my life in short.


How was last year?

Last year was quite good for me because I made a good performance on my work, did a presentation, and wrote a blog. I had anxiety and a sense of skepticism the year before last but I could study more and concentrate more on my work last year. What are the reasons? Those are like the below.

Work that contributes to the company

My previous workplace’s works were only for once and not continuous because all those works are advanced development. However, from the year before last to last year, it was a part that could contribute to the company and was essential for the future. There is no company where data is not needed and I think it is necessary because it seems that the company can get new insights through data.

I took a data collection part in the company’s big data department and it is a trend these days. Many public cloud companies are also presenting various technologies and seem to be publishing a lot of papers.

Going through solving difficulties

There were difficulties when integrating other services. While doing that our team solved many difficulties. There were some events solving requirements from the data source owner. Those works were quite worthwhile to me.

Writing blog steadily

Although the number of new posts decreased compared to the year before last. I kept writing my blog. Still, many things are left to write but I’m trying to write them. Visitors are decreasing but I don’t care about it much. I’m going to write the blog this year same as last year.

I feel like growing up

I grow up every year but I think last year was the most. Last year we tried sprint planning and event storming activity. In development, I studied a lot while thinking about how to collect data in the cloud such as AWS or GCP. Especially I studied more about cloud services and authentication. I learned about AWS IAM user and role and GCP service account. I searched each database’s fetch solution in AWS. Also, I tried Airflow, Dataflow, and VPC Endpoint related things. A little sad thing is… it was regrettable that I could not more focus on the server backend or code related parts.

Presentation which was my bucket list

It has been a dream that makes a presentation at our company event since I was young. Technically my dream is to present the products that I made at CES or MWC. Thankfully I was lucky that I could make a presentation at SSDC(Samsung Software Developer Conference) which is a small software event in our company. There were many other things like achieving my work goals but it is one of the most rewarding things last year. It’s not a big thing but I felt like I approached one step toward my dream.

As I wrote above, last year was good for me. Last year I thought about studying veterinary medicine and that part still remains in my mind. I’d like to work hard to develop my abilities and help somewhere. I still think about the way to help animals. I choose to make a lot of money and support them but… still, many things are left to do. I think I still have many goals in my mind. Ability to fully support my family and parents, help people who don’t even have a chance, help animals, and make something that can help catch bad people, and still, there are many goals. Except for these goals, there are actually many important things in life. I will write those things in my diary!

Were there any regrets? With that regret, I will organize the regrets and how I can become better than before.


Regrets and improvements

Focus more on code

This year I’m going to more focus on writing good codes than just implementing codes.

Concentrate more

I think I sometimes lost concentration when I do something. So I should make a habit to make better concentration.

Concentrate more when doing self-development

Especially when I study or do other things at home, my concentration disappears quickly. So I should focus on what I have to do and finish it faster.

It is good to have my product

I studied hard but I made no product last year. I’d like to make my product and release it this year. It can be a game or service.


About life

This time I wrote short than last year. It is because I don’t need to write long. I think company works and self developments(software, stock, economy, blog, game development, etc) will be similar to last year.

When I was young, I thought 30 years of me would achieve many things but I cannot sure how many things I achieved. I think I had many goals when I was young and growing up. Maybe because I read a lot of great personal biography I’d like to protect and develop our country which has been struggling and developed in difficult circumstances, I’d like to help good people who suffered from bad people and I’d like to help and contribute to the world. Of course! It’s the same now. I sometimes dream of achieving any of my previous goals and thinking that my life was “OK” before I died so many times later. Nowadays I’m interested in helping animals which need help.

The previous goals are important but the most important thing in my life is my happiness. Most of my happiness is from my family and my people. My family is more important than any previous goal. I regret that I could not care for my brother(dog) and family because I just cared for myself and focused on my success. After that, I’m trying to spend even one more minute with my family. I’d like to take care of my family and spend more time with them. Nothing is more important than my family.

This year I’m going to be independent of my current family and make a new family. I am looking forward to the future of me and my family living in a new home! I am worried about becoming the head of the household but I believe that everything will be fine in the future as I have lived so far. My first goal is to take care of my new family, my parents, and my brother(dog). As I said family is the most important! My most precious and important thing is my family!


Conclusion

I’m curious how I’ll write this next year! Let’s continue to work hard as I have done so far! Thanks to all that I have and work hard with humility!

virsh 명령어를 통해 QEMU KVM VM 인스턴스의 IP 주소를 찾아보자


환경

  • Linux
  • QEMU
  • KVM
  • virsh


사용법

  • 네트워크 선택
  • virsh net-list 명령어 사용
$ virsh net-list
 Name                 State      Autostart     Persistent
----------------------------------------------------------
 default              active     yes           yes
  • 선택한 네트워크에서 찾고자하는 VM 인스턴스의 IP 주소 확인
  • virsh net-dhcp-leases [네트워크 이름] 명령어 사용
$ virsh net-dhcp-leases default
 Expiry Time          MAC address        Protocol  IP address                Hostname        Client ID or DUID
-------------------------------------------------------------------------------------------------------------------
 2022-12-04 12:00:03  52:54:00:d2:2f:78  ipv4      192.168.123.163/24        twpower-vm      01:52:54:00:d2:2f:78


참고자료

Find IP address of QEMU KVM VM instance by using virsh command


Environment and Prerequisite

  • Linux
  • QEMU
  • KVM
  • virsh


Usage

  • Choose network
  • Use virsh net-list command
$ virsh net-list
 Name                 State      Autostart     Persistent
----------------------------------------------------------
 default              active     yes           yes
  • Check IP address of VM instance in chosen network
  • Use virsh net-dhcp-leases [network name] command
$ virsh net-dhcp-leases default
 Expiry Time          MAC address        Protocol  IP address                Hostname        Client ID or DUID
-------------------------------------------------------------------------------------------------------------------
 2022-12-04 12:00:03  52:54:00:d2:2f:78  ipv4      192.168.123.163/24        twpower-vm      01:52:54:00:d2:2f:78


Reference

netstat을 사용해 특정 포트를 사용하는 프로세스의 프로세스 아이디를 찾아보자


환경

  • Ubuntu
  • CentOS
  • netstat(8)


netstat을 사용해 특정 포트를 사용하는 프로세스의 프로세스 아이디 찾기

netstat

netstat -nltup | grep [port_number]

예시

twpower@twpower-private-server:~$ netstat -nltup | grep 8888
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
tcp        0      0 127.0.0.1:8888          0.0.0.0:*               LISTEN      622522/python3.9


netstat과 옵션

netstat

  • 네트워크 연결, 라우팅 테이블, 인터페이스 통계, 마스커레이드 연결 그리고 멀티캐스트 멤버십을 출력해준다.
NETSTAT(8)               Linux System Administrator's Manual              NETSTAT(8)

NAME
       netstat  -  Print  network connections, routing tables, interface statistics, masquerade connections, and multicast memberships

사용한 옵션

  • n: 호스트명이 아니라 숫자의 IP주소로 보여준다.
  • l: LISTEN 상태의 네트워크 연결과 유닉스 소켓을 보여준다.
  • t: TCP 프로토콜 데이터를 보여준다.
  • u: UDP 프로토콜 데이터를 보여준다.
  • p: 프로세스 아이디와 프로세스명을 보여준다.


참고자료

Find process id of process using specific port with netstat


Environment and Prerequisite

  • Ubuntu
  • CentOS
  • netstat(8)


Find process id of process using specific port with netstat

netstat

netstat -nltup | grep [port_number]

Usage

twpower@twpower-private-server:~$ netstat -nltup | grep 8888
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
tcp        0      0 127.0.0.1:8888          0.0.0.0:*               LISTEN      622522/python3.9


netstat and option

netstat

  • Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships
NETSTAT(8)               Linux System Administrator's Manual              NETSTAT(8)

NAME
       netstat  -  Print  network connections, routing tables, interface statistics, masquerade connections, and multicast memberships

Used Options

  • n: Show numeric IP address not hostname.
  • l: Show LISTEN state of network connections and unix sockets.
  • t: Show TCP protocol datas.
  • u: Show UDP protocol datas.
  • p: Show process id and name.


Reference