Fluentbit: Remove database used in tail inputs

This updates the fluentbit configuration for tail inputs to remove
the values for utilizing mysqlite databases to track its location
in each file it's configured to tail.  This is intended to reduce
the pressure fluentbit exerts on the host through writing to
/var/log/foo.db. To help mitigate large amounts of traffic
sent from fluentbit to fluentd upon a pod restart, this also
adds a throttle filter to fluentbit.

As a result, Fluentbit no longer needs a writable mount to its
hostPath on /var/log on the host.  Thus, this change includes
updating the Fluentbit daemonset's mount on /var/log to be
readOnly

Change-Id: If4381f4ff47e887f3ea10beded4f6172edaf08ba

fluent-logging/templates/daemonset-fluent-bit.yaml

@@ -122,6 +122,7 @@ spec:
               readOnly: true
             - name: varlog
               mountPath: /var/log
+              readOnly: true
             - name: varlibdockercontainers
               mountPath: /var/lib/docker/containers
               readOnly: true

fluent-logging/values.yaml

@@ -115,9 +115,16 @@ conf:
         Name: tail
         Tag: kernel
         Path: /var/log/kern.log
-        DB: /var/log/kern.db
         Mem_Buf_Limit: 5MB
-        DB.Sync: Normal
+        Buffer_Chunk_Size: 1M
+        Buffer_Max_Size: 1M
+    - containers_tail:
+        header: input
+        Name: tail
+        Tag: kube.*
+        Path: /var/log/containers/*.log
+        Parser: docker
+        Mem_Buf_Limit: 5MB
         Buffer_Chunk_Size: 1M
         Buffer_Max_Size: 1M
     - libvirt:
@@ -125,9 +132,7 @@ conf:
         Name: tail
         Tag: libvirt
         Path: /var/log/libvirt/libvirtd.log
-        DB: /var/log/libvirt.db
         Mem_Buf_Limit: 5MB
-        DB.Sync: Normal
         Buffer_Chunk_Size: 1M
         Buffer_Max_Size: 1M
     - qemu:
@@ -135,9 +140,7 @@ conf:
         Name: tail
         Tag: qemu
         Path: /var/log/libvirt/qemu/*.log
-        DB: /var/log/qemu.db
         Mem_Buf_Limit: 5MB
-        DB.Sync: Normal
         Buffer_Chunk_Size: 1M
         Buffer_Max_Size: 1M
     - kubelet:
@@ -146,9 +149,7 @@ conf:
         Tag: journal.*
         Path: ${JOURNAL_PATH}
         Systemd_Filter: _SYSTEMD_UNIT=kubelet.service
-        DB: /var/log/kubelet.db
         Mem_Buf_Limit: 5MB
-        DB.Sync: Normal
         Buffer_Chunk_Size: 1M
         Buffer_Max_Size: 1M
     - docker_daemon:
@@ -157,11 +158,16 @@ conf:
         Tag: journal.*
         Path: ${JOURNAL_PATH}
         Systemd_Filter: _SYSTEMD_UNIT=docker.service
-        DB: /var/log/docker.db
         Mem_Buf_Limit: 5MB
-        DB.Sync: Normal
         Buffer_Chunk_Size: 1M
         Buffer_Max_Size: 1M
+    - throttle_filter:
+        header: filter
+        Name: throttle
+        Match: "**"
+        Rate: 1000
+        Window: 300
+        Interval: 1s
     - libvirt_record_modifier:
         header: filter
         Name: record_modifier
@@ -196,17 +202,6 @@ conf:
           _SYSTEMD_UNIT: SYSTEMD_UNIT
           _UID: UID
           _TRANSPORT: TRANSPORT
-    - containers_tail:
-        header: input
-        Name: tail
-        Tag: kube.*
-        Path: /var/log/containers/*.log
-        Parser: docker
-        DB: /var/log/flb_kube.db
-        Mem_Buf_Limit: 5MB
-        DB.Sync: Normal
-        Buffer_Chunk_Size: 1M
-        Buffer_Max_Size: 1M
     - drop_fluentd_logs:
         header: output
         Name: "null"