meta-google: rsyslog: Disable ForwardToSyslog

In rsyslog, the logs are read via the journal files like with
`journalctl`. The socket used by ForwardToSyslog is not used at all
(`run/systemd/journal/syslog`), so we will disable the forwarding to
avoid unnecessary work.

With the logs spamming the CPU usage of systemd-journald went down
after this change.

Before:
Always top 1 or two in CPU usage,
```
PID USER       PRI  NI  VIRT   RES   SHR S  CPU%-MEM%   TIME+  Command
30892 root        20   0 23520 10108  9720 R  84.3  1.0  0:37.72 /usr/lib/systemd/systemd-journald
```

After:
Less CPU usage overall.
```
PID USER       PRI  NI  VIRT   RES   SHR S  CPU%-MEM%   TIME+  Command
30976 root        20   0 23520  7608  7216 R  40.8  0.8  2:32.36 /usr/lib/systemd/systemd-journald
```

Reference:
- https://www.freedesktop.org/software/systemd/man/journald.conf.html#Forwarding%20to%20traditional%20syslog%20daemons

Change-Id: I50cf868d63697fc9b72529863bb83d249f3275c7
Signed-off-by: Willy Tu <wltu@google.com>

2 files changed, 14 insertions, 0 deletions

diff --git a/meta-google/recipes-extended/rsyslog/rsyslog/journald.conf b/meta-google/recipes-extended/rsyslog/rsyslog/journald.conf
new file mode 100644
index 0000000000..019bd03011
--- /dev/null
+++ b/meta-google/recipes-extended/rsyslog/rsyslog/journald.conf
@@ -0,0 +1,2 @@
+[Journal]
+ForwardToSyslog=no
diff --git a/meta-google/recipes-extended/rsyslog/rsyslog_%.bbappend b/meta-google/recipes-extended/rsyslog/rsyslog_%.bbappend
index f81c9d72e6..ee75641cd8 100644
--- a/meta-google/recipes-extended/rsyslog/rsyslog_%.bbappend
+++ b/meta-google/recipes-extended/rsyslog/rsyslog_%.bbappend
@@ -2,6 +2,18 @@ FILESEXTRAPATHS:prepend:gbmc := "${THISDIR}/${PN}:"
 
 SRC_URI:append:gbmc = " \
   file://rsyslog.conf \
+  file://journald.conf \
 "
 
 PACKAGECONFIG:append:gbmc = " imjournal"
+
+FILES:${PN}:append:gbmc = "\
+    ${systemd_unitdir}/journald.conf.d/ \
+"
+
+# Set ForwardToSyslog=no
+# Disable forward journal to socket since that is not being used.
+do_install:append:gbmc() {
+  install -D -m0644 ${WORKDIR}/journald.conf \
+    ${D}${systemd_unitdir}/journald.conf.d/99-${PN}.conf
+}