systemd: process with fork() only shows logs after child exits
I have a program that fork()s and exits. Its child remains running for about 50 seconds, while it prints out messages each 5 seconds. When I run from a terminal it runs as expected, the parent exits, then the child prints 10 messages and exits too. I then created a systemd service unit with only this:
[Unit]
Description=Program that forks
Documentation=https://program5.example.com
[Service]
Type=forking
ExecStart=/root/fork
Apparently systemd works as it shows the main process active until the child exits, but checking journalctl or even looking at the program with systemctl status, the child messages on the screen only shows up after the child exits and the process is dead. Why is that?
linux systemd process fork journalctl
asked 5 hours ago
Adriano_epifasAdriano_epifas
83
add a comment |
I have a program that fork()s and exits. Its child remains running for about 50 seconds, while it prints out messages each 5 seconds. When I run from a terminal it runs as expected, the parent exits, then the child prints 10 messages and exits too. I then created a systemd service unit with only this:
[Unit]
Description=Program that forks
Documentation=https://program5.example.com
[Service]
Type=forking
ExecStart=/root/fork
Apparently systemd works as it shows the main process active until the child exits, but checking journalctl or even looking at the program with systemctl status, the child messages on the screen only shows up after the child exits and the process is dead. Why is that?
linux systemd process fork journalctl
asked 5 hours ago
Adriano_epifasAdriano_epifas
83
1
It's the buffering question yet again. See unix.stackexchange.com/questions/505146, unix.stackexchange.com/questions/285419 , unix.stackexchange.com/questions/164987 , unix.stackexchange.com/questions/68059 , unix.stackexchange.com/questions/206224 , and unix.stackexchange.com/questions/164987 .
– JdeBP
5 hours ago
add a comment |
I have a program that fork()s and exits. Its child remains running for about 50 seconds, while it prints out messages each 5 seconds. When I run from a terminal it runs as expected, the parent exits, then the child prints 10 messages and exits too. I then created a systemd service unit with only this:
[Unit]
Description=Program that forks
Documentation=https://program5.example.com
[Service]
Type=forking
ExecStart=/root/fork
Apparently systemd works as it shows the main process active until the child exits, but checking journalctl or even looking at the program with systemctl status, the child messages on the screen only shows up after the child exits and the process is dead. Why is that?
linux systemd process fork journalctl
asked 5 hours ago
Adriano_epifasAdriano_epifas
83
I have a program that fork()s and exits. Its child remains running for about 50 seconds, while it prints out messages each 5 seconds. When I run from a terminal it runs as expected, the parent exits, then the child prints 10 messages and exits too. I then created a systemd service unit with only this:
[Unit]
Description=Program that forks
Documentation=https://program5.example.com
[Service]
Type=forking
ExecStart=/root/fork
Apparently systemd works as it shows the main process active until the child exits, but checking journalctl or even looking at the program with systemctl status, the child messages on the screen only shows up after the child exits and the process is dead. Why is that?
linux systemd process fork journalctl
linux systemd process fork journalctl
asked 5 hours ago
Adriano_epifasAdriano_epifas
83
asked 5 hours ago
Adriano_epifasAdriano_epifas
83
asked 5 hours ago
Adriano_epifasAdriano_epifas
83
asked 5 hours ago
Adriano_epifasAdriano_epifas
83
asked 5 hours ago
Adriano_epifasAdriano_epifas
83
83
1
It's the buffering question yet again. See unix.stackexchange.com/questions/505146, unix.stackexchange.com/questions/285419 , unix.stackexchange.com/questions/164987 , unix.stackexchange.com/questions/68059 , unix.stackexchange.com/questions/206224 , and unix.stackexchange.com/questions/164987 .
– JdeBP
5 hours ago
add a comment |
1
It's the buffering question yet again. See unix.stackexchange.com/questions/505146, unix.stackexchange.com/questions/285419 , unix.stackexchange.com/questions/164987 , unix.stackexchange.com/questions/68059 , unix.stackexchange.com/questions/206224 , and unix.stackexchange.com/questions/164987 .
– JdeBP
5 hours ago
1
1
It's the buffering question yet again. See unix.stackexchange.com/questions/505146, unix.stackexchange.com/questions/285419 , unix.stackexchange.com/questions/164987 , unix.stackexchange.com/questions/68059 , unix.stackexchange.com/questions/206224 , and unix.stackexchange.com/questions/164987 .
– JdeBP
5 hours ago
It's the buffering question yet again. See unix.stackexchange.com/questions/505146, unix.stackexchange.com/questions/285419 , unix.stackexchange.com/questions/164987 , unix.stackexchange.com/questions/68059 , unix.stackexchange.com/questions/206224 , and unix.stackexchange.com/questions/164987 .
– JdeBP
5 hours ago
add a comment |
0
active
oldest
votes
Your Answer
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "106"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2funix.stackexchange.com%2fquestions%2f505411%2fsystemd-process-with-fork-only-shows-logs-after-child-exits%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
0
active
oldest
votes
0
active
oldest
votes
active
oldest
votes
active
oldest
votes
Thanks for contributing an answer to Unix & Linux Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2funix.stackexchange.com%2fquestions%2f505411%2fsystemd-process-with-fork-only-shows-logs-after-child-exits%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
1
It's the buffering question yet again. See unix.stackexchange.com/questions/505146, unix.stackexchange.com/questions/285419 , unix.stackexchange.com/questions/164987 , unix.stackexchange.com/questions/68059 , unix.stackexchange.com/questions/206224 , and unix.stackexchange.com/questions/164987 .
– JdeBP
5 hours ago