diff --git a/lib/kadeploy3/server/debug.rb b/lib/kadeploy3/server/debug.rb
index a2995689e4c7b19f97cf3c3f8552b4e35bf46dda..4761b2e6182e5058e602b669c38cb30517e1fa54 100644
--- a/lib/kadeploy3/server/debug.rb
+++ b/lib/kadeploy3/server/debug.rb
@@ -95,6 +95,12 @@ module Debug
       end
     end
 
+    def read()
+      @lock.synchronize do
+        @output
+      end
+    end
+
     def pop()
       @lock.synchronize do
         ret = @output
@@ -182,6 +188,21 @@ module Debug
       end
     end
 
+    def read(node = nil)
+      @lock.synchronize do
+        if node
+          @debug[node]
+        else
+          ret = ''
+          @debug.each_key do |n|
+            ret << @debug[n] if @debug[n]
+          end
+          (ret.empty? ? nil : ret)
+        end
+      end
+    end
+
+
     def empty?()
       ret = true
       @lock.synchronize do
diff --git a/lib/kadeploy3/server/kaworkflow.rb b/lib/kadeploy3/server/kaworkflow.rb
index b544676b8ef5955f1080718918596d97d4571e5c..ca8a683d7d933821c314ead2ac60a9ffec2b73a2 100644
--- a/lib/kadeploy3/server/kaworkflow.rb
+++ b/lib/kadeploy3/server/kaworkflow.rb
@@ -691,13 +691,13 @@ module Kaworkflow
       error_not_found! if info[:workflows] and cluster and !info[:workflows][cluster]
 
       if info[:workflows] and info[:workflows][cluster]
-        info[:workflows][cluster].output.pop unless info[:workflows][cluster].done?
+        info[:workflows][cluster].output.read unless info[:workflows][cluster].done?
       else
         log = ''
-        log << info[:output].pop
+        log << info[:output].read
         if info[:workflows]
           info[:workflows].each_value do |workflow|
-            log << workflow.output.pop unless workflow.done?
+            log << workflow.output.read unless workflow.done?
           end
         end
         log
@@ -710,7 +710,7 @@ module Kaworkflow
       break if info[:error]
       error_not_found! if (node and !info[:nodelist].include?(node)) or !info[:debugger]
 
-      info[:debugger].pop(node)
+      info[:debugger].read(node)
     end
   end
 
@@ -774,4 +774,3 @@ module Kaworkflow
 end
 
 end
-
diff --git a/vagrant-env/envs/debian9-x64-min.dsc b/vagrant-env/envs/debian9-x64-min.dsc
index 11567b629ac60da837f68aaf38f7b3293fe7f76a..37e375b577866c94767b13b86b958755e3c1634a 100644
--- a/vagrant-env/envs/debian9-x64-min.dsc
+++ b/vagrant-env/envs/debian9-x64-min.dsc
@@ -8,9 +8,9 @@ visibility: public
 destructive: false
 os: linux
 image:
-  file: server:///vagrant/envs/debian9-x64-min-2020090209.tgz
+  file: server:///vagrant/envs/debian9-x64-min.tar.zst
   kind: tar
-  compression: gzip
+  compression: zstd
 postinstalls:
 - archive: server:///grid5000/postinstalls/g5k-postinstall.tgz
   compression: gzip