User:Przemoc/Notes

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< User:Przemoc
Revision as of 18:43, 19 April 2016 by Przemoc (talk | contribs) (AL 3.3.3: Console/tmux)

I finally installed AL and I'm poking it a bit. Here you can find some notes regarding this experience. They should be helpful, but please use them with caution. I may add some additional commentary sometimes. If you think there is a better way to perform some of mentioned here tasks, then don't hesitate to notify me about it. Top-level headings denotes AL version that was used. Backward and forward compatibility is possible, but not tested.

Alpine Linux 3.3.3

Shell

Even though I always try to write POSIX sh-compliant scripts, I like to have bash as my default shell, because it's quite handy. Being able to write for instance quick diff -u <(COMMAND1) <(COMMAND2) (to compare output of two commands) or mv FILE{,SUFFIX} (to rename file by adding suffix) is very convenient.

Bash as default shell

AL doesn't have vipw, so root has to perform vi /etc/passwd himself to change the last field of root record (should be the first line in the file). You have to install util-linux package to get chsh utility.

Activate color prompt

Initial prompt: baytrail:~#

mv /etc/profile.d/color_prompt{,.sh}

Prompt after above change and relogin: baytrail [~]#

Long history

I like to have long history, so I created following file:

Contents of /etc/profile.d/long_history.sh

export HISTSIZE=9999999 export HISTFILESIZE=$HISTSIZE

Console

If you have physical access to screen connected to your machine with AL, it's nice to have properly configured console.

UTF-8 encoding

To have UTF-8 from OpenRC point of view, you have to set in /etc/rc.conf: 

unicode="YES"

and add /etc/init.d/termencoding to autostart:

rc-update add termencoding

In fact it's mostly irrelevant (prove me wrong).

Font with polish letters

To be able to see polish letters, you have to install kbd-misc package, set in /etc/conf.d/consolefont: 

consolefont="lat2-sun16.psfu.gz"
consoletranslation="8859-2_to_uni.trans"

and add /etc/init.d/consolefont to autostart:

rc-update add consolefont

If you don't like default default8x16.psf.gz font, then use lat2-16.psfu.gz instead. If you're comfortable with lower letter height, then I suggest using lat2-14.psfu.gz, which is still readable, yet on my 1920x1200 display increases LINES number from 75 to 85.

UTF-8 in tmux

tmux checks upon start-up whether environment variable LC_ALL, or if it's empty then LC_CTYPE, or if it's empty then LANG, contain string UTF-8 or UTF8 to activate its UTF-8 mode. It can be also triggered by -u option. Important part is that globally turning on utf8 window option in tmux configuration doesn't enforce UTF-8 mode.

musl has locale system since v1.1.4, it was incomplete and experimental, but I'm not sure how it is now. The thing is it's not leveraged by AL and by default you have no LC_* variables set. In musl built-in default is C.UTF-8, so we can simply create one file to set LC_CTYPE to such default value and it will satisfy tmux check:

Contents of /etc/profile.d/locale.sh

export LC_CTYPE=C.UTF-8

Possible alternative is to alias tmux to tmux -u, but it seems clunky.

Disk

Set up RAID1 on two devices

# install package
apk add mdadm

# load "raid1" module during boot (not really needed if you perform further steps)
echo raid1 >>/etc/modules

# create RAID1 array on two whole disks with 1MB data offset
mdadm --create --level=1 --raid-devices=2 --data-offset=1M /dev/md0 /dev/sda /dev/sdb

# preserve original example mdadm.conf
mv /etc/mdadm.conf{,.orig}

# save current setup into configuration file
# (usually people do not use -v, but it's more readable)
mdadm --detail -v --scan >/etc/mdadm.conf

# add raid devices starting to autostart
rc-update add mdadm-raid

# add raid devices monitoring to autostart
rc-update add mdadm

# start raid devices monitoring now
/etc/init.d/mdadm start

# following steps are needed if you want to support RAID early during boot

# add "raid" to features (space-separated values)
vi /etc/mkinitfs/mkinitfs.conf

# rebuild /boot/initramfs-grsec
mkinitfs

# add "raid1" to modules (comma-separated values)
vi /etc/update-extlinux.conf

# update extlinux
update-extlinux

Install smartctl and smartd

# install package
apk add smartmontools

# comment DEVICESCAN and uncomment DEVICESCAN -R 194 -R 231 -I 9
# to get meaningful and useful raw temperature in syslog
vi /etc/smartd.conf

# add smartd service to autostart
rc-update add smartd

# start the service now
/etc/init.d/smartd start

Sensors

lm_sensors

# install package
apk add lm_sensors

# install package for detecting sensors (if needed) - installs perl too
apk add lm_sensors-detect

# load module required for detecting sensors
modprobe i2c-dev

# detect sensors (skip scanning Super I/O, IPMI, ISA if you're on grsec)
sensors-detect

# after detecting sensors you can remove perl (if you don't need it)
apk del perl
Problems
  1. sensors-detect command created /etc/modules-load.d/lm_sensors.conf file, but its first line is a comment, which leads to following message during boot 
    modprobe: ERROR: missing parameters. See -h.

    It can be fixed by improving sed command in /etc/init.d/modules from 's/\#.*//g' to 's/\#.*//g;/^[ \t]*$/d' (deleting empty lines).

  2. It seems that nowadays you don't have to add lm_sensors to autostart, because in AL lm_sensors package is patched to create file /etc/modules-load.d/lm_sensors.conf (files in this directory are inspected by /etc/init.d/modules). /etc/init.d/lm_sensors seems in fact superfluous and it also doesn't work 
     * /etc/conf.d/lm_sensors does not exist, try running sensors-detect
 * ERROR: lm_sensors failed to start

    because it expects old file (/etc/conf.d/lm_sensors), which is no longer provided.

Todo: Report both issues on alpine-devel ML.


Mail

I don't need my own real mail server (as it's kind of PITA to set it up properly nowadays). Simple MTA is good enough. In the old days I used ssmtp, but it stopped being maintained (apparently debian devs maintain it now), so I switched to msmtp.

msmtp

After installing msmtp package, you need to create configuration file in your home directory. You can find example for Zoho Mail account.

Contents of ~/.msmtprc

defaults tls on tls_trust_file /etc/ssl/certs/ca-certificates.crt logfile ~/.msmtp.log auth on port 587 account yourname@zoho.com from yourname@zoho.com user yourname@zoho.com host smtp.zoho.com account default : yourname@zoho.com

You'll be asked for password every time mail is sent.

Problems

If you use gmail, then it's no longer that simple. After changing each zoho to gmail in above exemplary configuration, you still won't be able to send any mail. You'll get: 

msmtp: server message: 534-5.7.14 <https://accounts.google.com/signin/continue?sarp=1&scc=1&plt=...> Please log in via your web browser and then try again.
msmtp: server message: 534-5.7.14  Learn more at
msmtp: server message: 534-5.7.14  https://support.google.com/mail/answer/78754 ...

and you'll receive e-mail titled "Sign-in attempt prevented".

You have to turn on less secure apps if you want to deal with it. If you're using 2-step verification, then you'll have to add app password for msmtp.

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