最小安裝 ubuntu 的時候，預設都是設定 UTC +0 的時區，有時候真的很難對時間。
Ubuntu 只要透過安裝 tzdata 就可以設定預設時間了 sudo apt-get install tzdata
如果你已經設定過了，可以透過 sudo dpkg-reconfigure tzdata 重新設定。
詳細過程如下：
jangmt@instance-1-tokyo:/usr/share$ sudo apt-get install tzdata
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
tzdata
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 208 kB of archives.
After this operation, 3534 kB of additional disk space will be used.
Get:1 http://asia-northeast1.gce.archive.ubuntu.com/ubuntu eoan/main amd64 tzdata all 2019c-3 [208 kB]
Fetched 208 kB in 1s (171 kB/s)
debconf: delaying package configuration, since apt-utils is not installed
Selecting previously unselected package tzdata.
(Reading database ... 63700 files and directories currently installed.)
Preparing to unpack .../tzdata_2019c-3_all.deb ...
Unpacking tzdata (2019c-3) ...
Setting up tzdata (2019c-3) ...
debconf: unable to initialize frontend: Dialog
debconf: (No usable dialog-like program is installed, so the dialog based frontend cannot be used. at /usr/share/perl5/Debconf/FrontEnd/Dialog.pm line 76.)
debconf: falling back to frontend: Readline
Configuring tzdata
------------------
Please select the geographic area in which you live. Subsequent configuration questions will narrow this
down by presenting a list of cities, representing the time zones in which they are located.
1. Africa 3. Antarctica 5. Arctic 7. Atlantic 9. Indian 11. SystemV 13. Etc
2. America 4. Australia 6. Asia 8. Europe 10. Pacific 12. US
Geographic area: 6
Please select the city or region corresponding to your time zone.
1. Aden 16. Brunei 31. Hong_Kong 46. Kuala_Lumpur 61. Pyongyang 76. Tehran
2. Almaty 17. Chita 32. Hovd 47. Kuching 62. Qatar 77. Tel_Aviv
3. Amman 18. Choibalsan 33. Irkutsk 48. Kuwait 63. Qostanay 78. Thimphu
4. Anadyr 19. Chongqing 34. Istanbul 49. Macau 64. Qyzylorda 79. Tokyo
5. Aqtau 20. Colombo 35. Jakarta 50. Magadan 65. Rangoon 80. Tomsk
6. Aqtobe 21. Damascus 36. Jayapura 51. Makassar 66. Riyadh 81. Ujung_Pandang
7. Ashgabat 22. Dhaka 37. Jerusalem 52. Manila 67. Sakhalin 82. Ulaanbaatar
8. Atyrau 23. Dili 38. Kabul 53. Muscat 68. Samarkand 83. Urumqi
9. Baghdad 24. Dubai 39. Kamchatka 54. Nicosia 69. Seoul 84. Ust-Nera
10. Bahrain 25. Dushanbe 40. Karachi 55. Novokuznetsk 70. Shanghai 85. Vientiane
11. Baku 26. Famagusta 41. Kashgar 56. Novosibirsk 71. Singapore 86. Vladivostok
12. Bangkok 27. Gaza 42. Kathmandu 57. Omsk 72. Srednekolymsk 87. Yakutsk
13. Barnaul 28. Harbin 43. Khandyga 58. Oral 73. Taipei 88. Yangon
14. Beirut 29. Hebron 44. Kolkata 59. Phnom_Penh 74. Tashkent 89. Yekaterinburg
15. Bishkek 30. Ho_Chi_Minh 45. Krasnoyarsk 60. Pontianak 75. Tbilisi 90. Yerevan
Time zone: 73
Current default time zone: 'Asia/Taipei'
Local time is now: Sun Mar 29 19:17:53 CST 2020.
Universal Time is now: Sun Mar 29 11:17:53 UTC 2020.
Run 'dpkg-reconfigure tzdata' if you wish to change it.
jangmt@instance-1-tokyo:/usr/share$ timedatectl
Local time: Sun 2020-03-29 19:19:27 CST
Universal time: Sun 2020-03-29 11:19:27 UTC
RTC time: Sun 2020-03-29 11:19:28
Time zone: Asia/Taipei (CST, +0800)
System clock synchronized: yes
NTP service: inactive
RTC in local TZ: no
