Ukraine's account of who broke ceasefires is as reliable as Israel's. During period in question, ethnic Russians were being massacred by nationalists such as Azov battalion paramilitaries. You'd need to examine each of the 20 ceasefires without playing favorites to get an honest account, which I can't do. Overall, Ukraine was the definite aggressor during this period.
Is this so-called massacre this one? https://en.wikipedia.org/wiki/2014_Odesa_clashes where pro-Russian separatists attacked a peaceful rally by a much larger crowd, which led to an obviously just retaliation?