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<div class="moz-cite-prefix">On 4/4/19 5:52 am, JCA wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAFy1yb1YSFJJ3jiZYODZsMfbjMjksyp1N-__8eWqfJJbbU=gKw@mail.gmail.com">
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<div>My apologies for the length of this; I'd
rather give to much information than too little.</div>
<div><br>
</div>
<div dir="ltr">I have a simple PaceMaker cluster
with two nodes, A and B, that are CentOS 7 VMs.
In both nodes I have a file named my-data.res
under /etc/drdb.d, with the following contents
(identical in both nodes):</div>
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</div>
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<div dir="ltr"> resource my-data {</div>
<div dir="ltr"> protocol C;</div>
<div dir="ltr"> meta-disk internal;</div>
<div dir="ltr"> device /dev/drbd1;</div>
<div dir="ltr"><br>
</div>
<div dir="ltr"> syncer {</div>
<div dir="ltr"> verify-alg sha1;</div>
<div dir="ltr"> }</div>
<div dir="ltr"><br>
</div>
<div dir="ltr"> net {</div>
<div dir="ltr"> allow-two-primaries;</div>
<div dir="ltr"> }</div>
<div dir="ltr"> on A {</div>
<div dir="ltr"> disk /dev/sdb1;</div>
<div dir="ltr"> address <a
href="http://192.168.123.17:7789"
moz-do-not-send="true">192.168.0.5:7789</a>;</div>
<div dir="ltr"> }</div>
<div dir="ltr"><br>
</div>
<div dir="ltr"> on B {</div>
<div dir="ltr"> disk /dev/sdb1;</div>
<div dir="ltr"> address <a
href="http://192.168.123.20:7789"
moz-do-not-send="true">192.168.0.6:7789</a>;</div>
<div dir="ltr"> }</div>
<div dir="ltr"> }</div>
<div><br>
</div>
</div>
<div dir="ltr">In both A and B, I did the
following:<br>
</div>
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<div><br>
</div>
<div>
<div> # drbdadm create-md my-data</div>
<div> --== Thank you for participating in
the global usage survey ==--<br>
</div>
<div> The server's response is:</div>
<div><br>
</div>
<div> you are the xxxxxth user to install
this version</div>
<div> drbdmeta 1 v08 /dev/sdb1 internal
create-md</div>
<div><br>
</div>
<div> # drbdadm up my-data</div>
<div><br>
</div>
<div>In A alone, I did the following:</div>
<div><br>
</div>
<div> # drbdadm primary --force my-data</div>
</div>
<div><br>
</div>
<div>After this, and giving time for both nodes
to become synchronized, I get the following
in A:</div>
<div>
<div><br>
</div>
<div> # cat /proc/drbd</div>
<div> version: 8.4.11-1
(api:1/proto:86-101)<br>
</div>
<div> GIT-hash:
66145a308421e9c124ec391a7848ac20203bb03c
build by mockbuild@, 2018-11-03 01:26:55</div>
<div><br>
</div>
<div> 1: cs:Connected
ro:Primary/Secondary ds:UpToDate/UpToDate C
r-----ns:2096028 nr:0 dw:0 dr:2098148 al:8
bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:0</div>
<div><br>
</div>
<div>whereas the output from the same command
in B is</div>
<div><br>
</div>
<div> version: 8.4.11-1
(api:1/proto:86-101)<br>
</div>
<div> GIT-hash:
66145a308421e9c124ec391a7848ac20203bb03c
build by mockbuild@, 2018-11-03 01:26:55</div>
<div><br>
</div>
<div> 1: cs:Connected
ro:Secondary/Primary ds:UpToDate/UpToDate C
r-----ns:0 nr:2096028 dw:2096028 dr:0 al:8
bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:0</div>
<div><br>
</div>
</div>
<div>In A, I then created a filesystem in the
/dev/drbd1 device</div>
<div><br>
</div>
<div>
<div> # mkfs.ext4 /dev/drbd1</div>
<div><br>
</div>
<div>I then mounted it (stil in A) and
populated it with some data, consisting of
two files, f1 and f2, unmounting when done.</div>
<div><br>
</div>
</div>
<div>After this, I issued the following commands
in A:</div>
<div><br>
</div>
<div>
<div> # pcs cluster cib drbd_cfg</div>
<div> # pcs -f drbd_cfg resource create
DrbdData ocf:linbit:drbd
drbd_resource=my-data op monitor
interval=60s</div>
<div> # pcs -f drbd_cfg resource master
DrbdDataClone DrbdData master-max=1
master-node-max=1 clone-max=2
clone-node-max=1 notify=true</div>
<div> # pcs cluster cib-push drbd_cfg<br>
</div>
</div>
<div>
<div> # pcs cluster cib fs_cfg</div>
<div> # pcs -f fs_cfg resource create
DrbdFS Filesystem device="/dev/drbd1"
directory="/var/lib/my-data" fstype="ext4"</div>
</div>
<div> # pcs -f fs_cfg constraint
colocation add DrbdFS with DrbdDataClone
INFINITY with-rsc-role=Master</div>
<div>
<div> # pcs -f fs_cfg constraint order
promote DrbdDataClone then start DrbdFS</div>
<div> Adding DrbdDataClone DrbdFS
(kind: Mandatory) (Options:
first-action=promote then-action=start)</div>
<div> # pcs -f fs_cfg constraint
colocation add ClusterIP with DrbdFS
INFINITY</div>
<div> # pcs -f fs_cfg constraint order
DrbdFS then ClusterIP</div>
<div> Adding DrbdFS ClusterIP (kind:
Mandatory) (Options: first-action=start
then-action=start)</div>
<div> # pcs cluster cib-push fs_cfg</div>
<div> CIB Updated</div>
<div> # pcs status resources</div>
<div> ClusterIP
(ocf::heartbeat:IPaddr2): Started A</div>
<div> Master/Slave Set: DrbdDataClone
[DrbdData]</div>
<div> Masters: [ A ]</div>
<div> Slaves: [ B ]</div>
<div> DrbdFS
(ocf::heartbeat:Filesystem): Started A</div>
</div>
<div><br>
</div>
<div>The output from the last command in B is
very similar, mutatis mutandis.</div>
<div><br>
</div>
<div>Once this all is done, node A is active
where node B is passive. When I do </div>
<div><br>
</div>
<div> # ls /var/lib/my-data</div>
<div><br>
</div>
<div>in A I can see the f1 and f2 files that I
created above. In B, however, there is
nothing. My understanding of the DRBD
framework tells me that this is expected.</div>
<div><br>
</div>
<div>During this state of affairs (i.e. the
cluster up both in A and B, with A being the
active node and B being the passive node) I
stopped the A node by issuing the following
command in A:</div>
<div><br>
</div>
<div> # pcs cluster stop A</div>
<div><br>
</div>
<div>After this, and giving time for node B to
take over, I get the following in B:</div>
<div><br>
</div>
<div>
<div> # pcs status</div>
<div> Cluster name: FirstCluster</div>
<div> Stack: corosync</div>
<div> Current DC: B (version
1.1.19-8.el7_6.4-c3c624ea3d) - partition
with quorum</div>
<div> Last updated: Wed Apr 3
11:49:19 2019</div>
<div> Last change: Wed Apr 3
09:53:30 2019 by root via cibadmin on B</div>
<div><br>
</div>
<div> 2 nodes configured</div>
<div> 4 resources configured</div>
<div><br>
</div>
<div> Online: [ B ]</div>
<div> OFFLINE: [ A ]</div>
<div><br>
</div>
<div> Full list of resources:</div>
<div><br>
</div>
<div> ClusterIP<span style="white-space:pre"> </span>(ocf::heartbeat:IPaddr2):<span style="white-space:pre"> </span>Started
B</div>
<div> Master/Slave Set:
DrbdDataClone [DrbdData]</div>
<div> Masters: [ B ]</div>
<div> Stopped: [ A ]</div>
<div> DrbdFS<span style="white-space:pre"> </span>(ocf::heartbeat:Filesystem):<span style="white-space:pre"> </span>Started
B</div>
<div><br>
</div>
<div> Daemon Status:</div>
<div> corosync: active/enabled</div>
<div> pacemaker: active/enabled</div>
<div> pcsd: active/enabled</div>
</div>
<div><br>
</div>
<div>On listing the contents of /var/lib/my-data
on A, nothing is found there. However, on
listing the contents of /var/lib/my-data on B,
I find files f1 and f2. So, B has taken over
and is now accessing, thanks to DRDB, the
filesystem created in A earlier on.</div>
<div><br>
</div>
<div>Next I started and stopped both A and B
(the nodes, not the VMs) until I got back the
original situation - namely, A is active, B is
passive, /var/log/my-data contains f1 and f2
in A, and nothing in B.</div>
<div><br>
</div>
<div>Next I did the following: In A I removed
both f1 and f2, and added new files, f3, and
f4. I did this while A is the active node.
After this I stopped the A node from A as
above. Having done this, the output from pcs
status in B is as described above. Here's the
thing:</div>
<div><br>
</div>
<div>In this situation, when I list the contents
of /var/lib/my-data in A, I find it to be
empty - as expected, for A has been stopped.
When I list the contents of /var/lib/my-data
in B, however, what I see is files f1 and f2,
not f3 and f4. I was expecting for any changes
made on /var/lib/my-data while A was active to
be made visible to B when it takes over.</div>
<div><br>
</div>
<div>Is my expectation misplaced? Or perhaps the
changes to /var/lib/my-data have to be made by
some resource explicitly managed by PaceMaker,
while changes done by hand are just dismissed?
Notice, however, that if I bring the A node up
again, and make it active, on listing
/var/lib/my-data on A I see files f3 and f4:
the changes I made by hand have not just been
dismissed.</div>
<div><br>
</div>
<div>As you can see, I am very confused.</div>
<div><br>
</div>
<br>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</blockquote>
<p>I have no idea what all your cluster management commands do, but
it sounds like you are mounting the underlying device on A instead
of the DRBD device. Thus, the changes you make are not replicated
to B.</p>
<p>While A is active and you see f3 and f4, run df /var/lib/my-data
and provide the output here, or just note that if the device is
not /dev/drbd<something> then you have made this mistake.<br>
</p>
<p>Hope that this helps...</p>
<p>Regards,<br>
Adam<br>
</p>
<div class="moz-signature">-- <br>
Adam Goryachev
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