ubuntu 20.04 + VirtalBox installation procedure summary
Since ubuntu 20.04 was introduced, the procedure is summarized.
The installation proceeded by creating a VirtualBox virtual machine in advance and mounting the ISO image.
Get the installer
Click here to get the ubuntu installer. I got the latest version 20.04 LTS at the time of writing the article.
https://jp.ubuntu.com/download
- LTS: LTS is an abbreviation for long-term support. Free security and maintenance updates are guaranteed for 5 years until April 2025. (Kopipe)
Installation procedure
The installation was done with GUI. Enter only the user name. When I selected the disk as standard without customizing it, it was installed in UEFI mode.
Disk configuration after installation
The virtual disk size assigned to VirtalBox is 16GB VDI format. The display of the df and fdsik commands is as follows.
$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 1.6G 0 1.6G 0% /dev
tmpfs 325M 1.4M 324M 1% /run
/dev/sda5 16G 7.4G 7.1G 51% /
tmpfs 1.6G 0 1.6G 0% /dev/shm
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 1.6G 0 1.6G 0% /sys/fs/cgroup
/dev/loop0 55M 55M 0 100% /snap/core18/1880
/dev/loop1 56M 56M 0 100% /snap/core18/1944
/dev/loop2 256M 256M 0 100% /snap/gnome-3-34-1804/36
/dev/loop3 218M 218M 0 100% /snap/gnome-3-34-1804/60
/dev/loop4 63M 63M 0 100% /snap/gtk-common-themes/1506
/dev/loop5 65M 65M 0 100% /snap/gtk-common-themes/1514
/dev/loop6 50M 50M 0 100% /snap/snap-store/467
/dev/loop7 52M 52M 0 100% /snap/snap-store/518
/dev/loop8 30M 30M 0 100% /snap/snapd/8542
/dev/loop9 32M 32M 0 100% /snap/snapd/10492
/dev/sda1 511M 4.0K 511M 1% /boot/efi
tmpfs 325M 36K 325M 1% /run/user/125
tmpfs 325M 8.0K 325M 1% /run/user/1000
$ sudo fdisk /dev/sda
：
command(Help with m): p
disk/dev/sda: 16 GiB,17179869184 bytes,33554432 sector
Disk model: VBOX HARDDISK
unit:sector(1 * 512 =512 bytes)
Sector size(logic/Physics):512 bytes/512 bytes
I/O size(minimum/Recommendation):512 bytes/512 bytes
Disc label type: dos
Disc identifier: 0x89cd8bc1
Device boot start position Last sector size Id type
/dev/sda1 * 2048 1050623 1048576 512M b W95 FAT32
/dev/sda2 1052670 33552383 32499714 15.5G 5 extended area
/dev/sda5 1052672 33552383 32499712 15.5G 83 Linux
Version confirmation
There are two types of confirmation methods. / etc/lsb-release is enough, but is it/etc/os-release that makes it easier to remember the path?
$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.1 LTS"
$ cat /etc/os-release
NAME="Ubuntu"
VERSION="20.04.1 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.1 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal
root password setting
By default ubuntu does not have a password set for root and cannot do su -. Set as follows.
$ sudo passwd root
new password:
Please re-enter your new password:
passwd:Password updated correctly
network settings
Immediately after installation, the IP address is assigned as shown below by default, a NAT interface is created, and you can connect to the Internet.
$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 08:00:27:5b:a0:4c brd ff:ff:ff:ff:ff:ff
inet 10.0.2.15/24 brd 10.0.2.255 scope global dynamic noprefixroute enp0s3
valid_lft 58625sec preferred_lft 58625sec
inet6 fe80::6a5e:debe:3fe6:d921/64 scope link noprefixroute
valid_lft forever preferred_lft forever
Set the host-only adapter on the VirtualBox side for TeraTerm access from the terminal. The network address should be different on the terminal side and ubuntu side in the same segment.
The ubuntu side is also set with GUI. Where is the network configuration file ...
DNS settings
DNS is also set, and name resolution is possible. Almost never set.
$ nslookup google.com
Server: 127.0.0.53
Address: 127.0.0.53#53
Non-authoritative answer:
Name: google.com
Address: 172.217.174.110
Name: google.com
Address: 2404:6800:4004:80b::200e
The DNS server address is specified as 127.0.0.53. This address is special and goes to see the systemd-resolved settings.
$ sudo cat /etc/resolv.conf
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients to the
# internal DNS stub resolver of systemd-resolved. This file lists all
# configured search domains.
#
# Run "resolvectl status" to see details about the uplink DNS servers
# currently in use.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 127.0.0.53
options edns0 trust-ad
In the systemd-resolved setting, the gateway address of the NAT connection destination terminal was set. It seems that it depends on the Internet connection environment of the terminal with VirtualBox, but there is no reason to change it, so leave it as it is this time.
kana@kana-VirtualBox:~$ systemd-resolve --status
Global
LLMNR setting: no
MulticastDNS setting: no
DNSOverTLS setting: no
DNSSEC setting: no
DNSSEC supported: no
DNSSEC NTA: 10.in-addr.arpa
16.172.in-addr.arpa
168.192.in-addr.arpa
17.172.in-addr.arpa
18.172.in-addr.arpa
19.172.in-addr.arpa
20.172.in-addr.arpa
21.172.in-addr.arpa
22.172.in-addr.arpa
23.172.in-addr.arpa
24.172.in-addr.arpa
25.172.in-addr.arpa
26.172.in-addr.arpa
27.172.in-addr.arpa
28.172.in-addr.arpa
29.172.in-addr.arpa
30.172.in-addr.arpa
31.172.in-addr.arpa
corp
d.f.ip6.arpa
home
internal
intranet
lan
local
private
test
Link 3 (enp0s8)
Current Scopes: none
DefaultRoute setting: no
LLMNR setting: yes
MulticastDNS setting: no
DNSOverTLS setting: no
DNSSEC setting: no
DNSSEC supported: no
Link 2 (enp0s3)
Current Scopes: DNS
DefaultRoute setting: yes
LLMNR setting: yes
MulticastDNS setting: no
DNSOverTLS setting: no
DNSSEC setting: no
DNSSEC supported: no
Current DNS Server: 192.168.11.1
DNS Servers: 192.168.11.1
DNS Domain: ~.
X-Window display size
The default 800x600 is hard to see, so set it to the right size.
Software update
On the console side of VirtualNBox, a notification that ubuntu software update is possible was displayed, so update it just in case. If you want to display it manually, select `Software Update from the menu at the bottom left.
It takes a long time to apply depending on the environment, so it is good to do it in some time. Estimate 30 minutes to 1 hour. After updating, open Software Update and the following dialog box will be displayed.
Introduced openssh-server
The ubuntu package management command is apt, and it is installed as follows.
$ sudo apt-get install openssh-server
After installing the package, let's check the service startup status.
$ sudo systemctl status sshd
● ssh.service - OpenBSD Secure Shell server
Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)
Active: active (running) since Sat 2020-12-26 10:48:19 JST; 8h ago
Docs: man:sshd(8)
man:sshd_config(5)
Process: 634 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=0/SUCCESS)
Main PID: 644 (sshd)
Tasks: 1 (limit: 3829)
Memory: 4.6M
CGroup: /system.slice/ssh.service
mq644 sshd: /usr/sbin/sshd -D [listener] 0 of 10-100 startups
Summary
Since it is the minimum setting, I hope that you can set it according to the application from here onwards. I hope it will be helpful for beginners.
Thank you for reading.
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