Re: [cip-dev][isar-cip-core]RFC v2 6/9] Create systemd mount units for a etc overlay

From: Gylstorff Quirin <quirin.gylstorff@siemens.com>
To: cip-dev@lists.cip-project.org
Subject: Re: [cip-dev][isar-cip-core]RFC v2 6/9] Create systemd mount units for a etc overlay
Date: Thu, 18 Nov 2021 19:12:42 +0100	[thread overview]
Message-ID: <fcfd6bd1-12b0-cb73-e416-19d4d0e0a6f1@siemens.com> (raw)
In-Reply-To: <20211117121131.as2eyks3q76x75sq@MD1ZFJVC.ad001.siemens.net>

On 11/17/21 1:11 PM, Christian Storm via lists.cip-project.org wrote:
>> From: Quirin Gylstorff <quirin.gylstorff@siemens.com>
>>
>> As /etc is read-only and needs to be accessed by the initrd
>> move the user defined settings to a overlay in /var/local/etc.
>>
>> Signed-off-by: Quirin Gylstorff <quirin.gylstorff@siemens.com>
>> ---
>>   .../etc-overlay-fs/etc-overlay-fs_0.1.bb         | 16 ++++++++++++++++
>>   .../etc-overlay-fs/files/etc-hostname.service    | 14 ++++++++++++++
>>   .../etc-overlay-fs/files/etc-sysusers.service    | 14 ++++++++++++++
>>   recipes-core/etc-overlay-fs/files/etc.mount      | 13 +++++++++++++
>>   .../files/overlay-parse-etc.service              | 12 ++++++++++++
>>   recipes-core/etc-overlay-fs/files/postinst       |  6 ++++++
>>   recipes-core/images/cip-core-image-read-only.bb  |  1 +
>>   7 files changed, 76 insertions(+)
>>   create mode 100644 recipes-core/etc-overlay-fs/etc-overlay-fs_0.1.bb
>>   create mode 100644 recipes-core/etc-overlay-fs/files/etc-hostname.service
>>   create mode 100644 recipes-core/etc-overlay-fs/files/etc-sysusers.service
>>   create mode 100644 recipes-core/etc-overlay-fs/files/etc.mount
>>   create mode 100644 recipes-core/etc-overlay-fs/files/overlay-parse-etc.service
>>   create mode 100755 recipes-core/etc-overlay-fs/files/postinst
>>
>> diff --git a/recipes-core/etc-overlay-fs/etc-overlay-fs_0.1.bb b/recipes-core/etc-overlay-fs/etc-overlay-fs_0.1.bb
>> new file mode 100644
>> index 0000000..f1c8349
>> --- /dev/null
>> +++ b/recipes-core/etc-overlay-fs/etc-overlay-fs_0.1.bb
>> @@ -0,0 +1,16 @@
>> +inherit dpkg-raw
>> +
>> +SRC_URI = "file://postinst \
>> +           file://etc.mount \
>> +           file://overlay-parse-etc.service \
>> +           file://etc-hostname.service \
>> +           file://etc-sysusers.service"
>> +
>> +do_install[cleandirs]+="${D}/lib/systemd/system ${D}/var/local/etc ${D}/var/local/.atomic"
>> +do_install() {
>> +    TARGET=${D}/lib/systemd/system
>> +    install -m 0644 ${WORKDIR}/etc.mount ${TARGET}/etc.mount
>> +    install -m 0644 ${WORKDIR}/overlay-parse-etc.service  ${TARGET}/overlay-parse-etc.service
>> +    install -m 0644 ${WORKDIR}/etc-hostname.service ${TARGET}/etc-hostname.service
>> +    install -m 0644 ${WORKDIR}/etc-sysusers.service ${TARGET}/etc-sysusers.service
>> +}
>> diff --git a/recipes-core/etc-overlay-fs/files/etc-hostname.service b/recipes-core/etc-overlay-fs/files/etc-hostname.service
>> new file mode 100644
>> index 0000000..2306b9f
>> --- /dev/null
>> +++ b/recipes-core/etc-overlay-fs/files/etc-hostname.service
>> @@ -0,0 +1,14 @@
>> +[Unit]
>> +Description=set hostname /etc overlay-aware
>> +Before=network-pre.target
>> +Wants=network-pre.target
>> +Requires=etc.mount
>> +After=etc.mount
>> +
>> +[Service]
>> +Type=oneshot
>> +RemainAfterExit=yes
>> +ExecStart=/bin/hostname --boot --file /etc/hostname
>> +
>> +[Install]
>> +WantedBy=basic.target
>> diff --git a/recipes-core/etc-overlay-fs/files/etc-sysusers.service b/recipes-core/etc-overlay-fs/files/etc-sysusers.service
>> new file mode 100644
>> index 0000000..6caf6b0
>> --- /dev/null
>> +++ b/recipes-core/etc-overlay-fs/files/etc-sysusers.service
>> @@ -0,0 +1,14 @@
>> +[Unit]
>> +Description=make systemd-sysusers /etc overlay aware
>> +Before=network-pre.target
>> +Wants=network-pre.target
>> +Requires=etc.mount
>> +After=etc.mount
>> +
>> +[Service]
>> +Type=oneshot
>> +RemainAfterExit=yes
>> +ExecStart=/usr/bin/systemd-sysusers
>> +
>> +[Install]
>> +WantedBy=basic.target
> 
> Hm, why do you replace/create those services instead of augmenting the
> current default ones via conf.d'lets?
> Why is this one here dependent on network?
> Why does this differ that much from upstream service files, see, e.g.,
> https://github.com/systemd/systemd/blob/main/units/systemd-sysusers.service
> 

You right thats the better solution. Will test it and add it in a v3.

> 
>> diff --git a/recipes-core/etc-overlay-fs/files/etc.mount b/recipes-core/etc-overlay-fs/files/etc.mount
>> new file mode 100644
>> index 0000000..f0ae3c5
>> --- /dev/null
>> +++ b/recipes-core/etc-overlay-fs/files/etc.mount
>> @@ -0,0 +1,13 @@
>> +[Unit]
>> +Description=Overlay-mount /etc
>> +Requires=var.mount
>> +After=var.mount
>> +
>> +[Mount]
>> +What=overlay
>> +Where=/etc
>> +Type=overlay
>> +Options=noauto,x-systemd.automount,lowerdir=/etc,upperdir=/var/local/etc,workdir=/var/local/.atomic
>> +
>> +[Install]
>> +WantedBy=local-fs.target
>> diff --git a/recipes-core/etc-overlay-fs/files/overlay-parse-etc.service b/recipes-core/etc-overlay-fs/files/overlay-parse-etc.service
>> new file mode 100644
>> index 0000000..062bb40
>> --- /dev/null
>> +++ b/recipes-core/etc-overlay-fs/files/overlay-parse-etc.service
>> @@ -0,0 +1,12 @@
>> +[Unit]
>> +Description=Reload Configuration from the etc overlay
>> +Requires=etc.mount
>> +After=etc.mount
>> +
>> +[Service]
>> +Type=oneshot
>> +RemainAfterExit=yes
>> +ExecStartPre=!/bin/systemctl daemon-reload
>> +ExecStart=!/bin/systemctl --no-block isolate multi-user.target
> 
> Wow, this is a big cannon, why do you need this? Isn't there another way?

After testing in the current cip-core-image i don't need it.

Quirin
> 
> 
>> +[Install]
>> +WantedBy=local-fs.target
>> diff --git a/recipes-core/etc-overlay-fs/files/postinst b/recipes-core/etc-overlay-fs/files/postinst
>> new file mode 100755
>> index 0000000..35641af
>> --- /dev/null
>> +++ b/recipes-core/etc-overlay-fs/files/postinst
>> @@ -0,0 +1,6 @@
>> +#!/bin/sh
>> +
>> +deb-systemd-helper enable etc.mount  || true
>> +deb-systemd-helper enable overlay-parse-etc.service || true
>> +deb-systemd-helper enable etc-hostname.service || true
>> +deb-systemd-helper enable etc-sysusers.service || true
>> diff --git a/recipes-core/images/cip-core-image-read-only.bb b/recipes-core/images/cip-core-image-read-only.bb
>> index 7ef2dc2..ceb6ac4 100644
>> --- a/recipes-core/images/cip-core-image-read-only.bb
>> +++ b/recipes-core/images/cip-core-image-read-only.bb
>> @@ -2,6 +2,7 @@ require cip-core-image.bb
>>   
>>   SQUASHFS_EXCLUDE_DIRS += "home var"
>>   
>> +IMAGE_INSTALL += "etc-overlay-fs"
>>   IMAGE_INSTALL += "tmp-fs"
>>   IMAGE_INSTALL_remove += "initramfs-abrootfs-secureboot"
>>   
>> -- 
>> 2.30.2
>>
> 
> 
> 
> Kind regards,
>     Christian
> 
> 
> 
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